GPRbuild is a generic build tool designed for the construction of
large multi-language systems organized into subsystems and libraries.
It is well-suited for compiled languages supporting separate compilation,
such as Ada, C, C++ or Fortran.
GPRbuild manages a three step build process
Each compilation unit of each subsystem is examined in turn, checked for consistency, and compiled or recompiled when necessary by the appropriate compiler. The recompilation decision is based on dependency information that is typically produced by a previous compilation.
Compiled units from a given language are passed to a language-specific post-compilation tool if any. Also during this phase objects are grouped into static or dynamic libraries as specified.
All units or libraries from all subsystems are passed to a linker tool specific to the set of toolchains being used.
GPRbuild takes as its main input a project file <file>.gpr
defining the build characteristics of the system under construction
such as:
The tool is generic in that it provides, when possible, equivalent build capabilities for all supported languages. For this, it uses a configuration file <file>.cgpr that has a syntax and structure very similar to a project file, but which defines the characteristics of the supported languages and toolchains. The configuration file contains information such as:
On the other hand, GPRbuild is not a replacement for general-purpose
build tools such as make or ant which give the user a high
level of control over the build process itself. When building a system
requires complex actions that do not fit well in the three-phase process
described above, GPRbuild might not be sufficient.
In such situations, GPRbuild can still
be used to manage the appropriate part of the build. For
instance it can be called from within a Makefile.
This chapter presents examples ranging from simple multi-language builds to some of the most advanced scenarios. All the examples shown in the text are included in the GPRbuild package, which is installed on your system in <prefix>/share/examples/gprbuild/.
GPRbuild requires one configuration file describing the languages and
toolchains to be used, and project files describing the
characteristics of the user project. Typically the configuration
file can be created automatically by GPRbuild based on the languages
defined in your projects and the compilers on your path. In more
involved situations – such as cross compilation, or
environments with several compilers for the same language –
you may need to control more precisely the generation of
the desired configuration of toolsets. A tool, GPRconfig, described in
Configuring with GPRconfig), offers this capability. In this
chapter most of the examples can use autoconfiguration.
GPRbuild will start its build process by trying to locate a configuration
file called default.cgpr.
If such a file is not available or if the option
--autoconf=xxx is used, GPRbuild will create its own configuration
file suitable for native development and assuming that there are known
compilers on your path for each of the necessary languages. It is
preferable and often necessary to manually generate your own
configuration file when:
GPRconfig provides several ways of generating configuration files. By default, a simple interactive mode lists all the known compilers for all known languages. You can then select a compiler for each of the languages; once a compiler has been selected, only compatible compilers for other languages are proposed. Here are a few examples of GPRconfig invocation:
<gprbuild_install_root>/share/gpr/default.cgpr)
gprconfig
gprconfig -o path/my_config.cgpr
gprbuild --config=path/my_config.cgpr
gprconfig --target=ppc-elf
gprconfig --config=Ada --config=C --batch
hi and using C for the LEON processor.
gprconfig --target=leon-elf --config=Ada,,hi --config=C --batch -o x.cgpr
Assume a simple case of interfacing between Ada and C where the main program is first in Ada and then in C. For a main program in Ada the following project may be used:
project Ada_Main is
for Languages use ("Ada", "C");
for Source_Dirs use ("ada_src", "util_src");
for Object_Dir use "obj";
for Exec_Dir use ".";
for Source_Files use ("ada_main.adb", "c_lib.ads", "lib.h", "lib.c");
for Main use ("ada_main.adb");
end Ada_Main;
This project indicates that:
ada_src and
util_src.
obj.
ada_main.adb,
c_lib.ads, lib.h, lib.c. They can be found anywhere
in the source directories mentioned above.
ada_main.adb.
This information is sufficient for GPRbuild to build an executable
program from the sources. Note that no direct indication on how to build
the various elements is given in the project file, which describes
the project properties rather than a set of actions to
be executed. Here is the invocation of
GPRbuild that allows building the multi-language program:
$ gprbuild -Pada_main
gcc -c ada_main.adb -o ada_main.o
gcc -c c_lib.ads -o c_lib.o
gcc -c lib.c -o lib.o
gprbind ada_main
...
gcc ada_main.o -o ada_main.exe
Notice the three steps described in the Introduction:
The default output of
GPRbuild's execution is kept reasonably simple and easy to understand.
In particular, some of the less frequently used commands
are not shown, and some parameters are abbreviated. GPRbuild's option
-v
provides a much more verbose output which includes, among other
information, more complete compilation, post-compilation and
link commands.
To illustrate some other GPRbuild capabilities, here is a slightly different project using similar sources and a main program in C:
project C_Main is
for Languages use ("Ada", "C");
for Source_Dirs use ("c_src", "util_src");
for Object_Dir use "obj1";
for Main use ("c_main.c");
package Compiler is
C_Switches := ("-pedantic");
for Default_Switches ("C") use C_Switches;
for Default_Switches ("Ada") use ("-gnaty");
for Switches ("c_main.c") use C_Switches & ("-g");
end Compiler;
end C_Main;
This project has many similarities with the previous one, as evident in
the Languages,
Source_Dirs and Object_Dirs attributes.
As expected, its Main attribute
now refers to a C source. The first noticeable difference is the lack of a
Source_Files attribute. When not specified explicitly, this attribute
has
an implicit value which is the complete set of sources of the given
Languages to
be found in Source_Dirs. Many attributes can be left implicit and will
be given
reasonable default values. For instance, Source_Dirs and
Object_Dir
default to the current directory (where the project file resides). The
Exec_Dir attribute defaults to the value of Object_Dir.
The other notable difference in this new project is the presence of the
package Compiler, which groups the attributes specific to
the compilation phases. The Default_Switches attribute provides the
list of compilation switches to be used for any source of a given
Languages value unless the source has its own set of compilation
switches
specified by the attribute Switches. Note also the use of a the
variable
C_Switches. A project variable can be useful to avoid duplication of
information and
here ensures that the file c_main.c is always compiled
with the default switches (whatever they may be), plus -g. In this
specific
situation the use of a variable could have been replaced by a reference
to the Default_Switches attribute:
for Switches ("c_main.c") use Compiler'Default_Switches ("C") & ("-g");
Here is the output of the GPRbuild command using this project:
$gprbuild -Pc_main
gcc -c -pedantic -g c_main.c -o c_main.o
gcc -c -gnaty ada_lib.adb -o ada_lib.o
gcc -c -gnaty c_lib.ads -o c_lib.o
gcc -c -pedantic lib.c -o lib.o
gprbind c_main
...
gcc c_main.o -o c_main.exe
The switches for compiling Ada sources,
the default switches for C sources in the compilation of lib.c,
and the specific switches for c_main.c have all been taken into
account.
When comparing this GPRbuild output with the previous one,
notice that there are common sources between the two projects, namely
c_lib.ads and lib.c. Those sources were compiled twice, once for
each
project. This is not surprising, since the two projects
are independent and have different Object_Dirs even though they share
some sources. It is possible to share more than the sources, and thus
avoid unnecessary recompilations when compilation units are
used in several different projects, by splitting a system into
subsystems.
The common compilation units may be grouped in a separate subsystem with
its own project file and a specified Object_Dir attribute:
project Common_Subsystem is
for Source_Dirs use ("util_src");
for Object_Dir use "obj_util";
end Common_Subsystem;
By default, all the sources in directory util_src belong to
project Common_Subsystem, and when compiled, their objects go in
obj_dir.
Other projects, whose sources depend on sources in util_src, can create
a dependency relationship using a project with clause:
with "Common_Subsystem";
project Ada_Main is
for Languages use ("Ada");
for Source_Dirs use ("ada_src");
...
end Ada_Main;
The Ada_Main.Source_Dirs no longer includes util_src. The
main program in ada_src still needs sources from util_src to be
compiled.
It also needs those units built. Now they will be compiled using the build
properties defined in Common_Subsystem instead of those of
Ada_Main.
The
project's with clause has several effects. It provides visibility of
sources during the compilation process as if the units from Ada_Main
were
compiled with an implicit -Iutil_src option. It also guarantees that the
necessary units from Common_Subsystem are available for
Ada_Main's linking
phase.
It is also possible to use the with relationship to define a project
file
that allows sharing common attributes or packages. For instance, you can
define a project whose only purpose is to centralize the default
compilation options for various languages:
project Attribute_Sharing is
for Source_Files use ();
package Compiler is
for Default_Switches ("C") use ("-pedantic");
for Default_Switches ("Ada") use ("-gnaty");
end Compiler;
end Attribute_Sharing;
This package does not correspond to a subsystem with
proper source files, and this is conveyed by the definition of
Source_Files
as the empty list. It informs the build manager
that no compilation is to take place directly from this project. Defining
an empty list of sources is essential for such utility projects because
otherwise the default rules would apply and all sources in the current
directory
would be associated with this project. Now other projects can share this
project's attributes and packages. For instance, Ada_Main can share all
the
Compiler package's attributes at once using a renaming declaration:
with "Attribute_Sharing";
...
project Ada_Main is
...
package Compiler renames Attribute_Sharing.Compiler;
end Ada_Main;
or if other aspects of the Compiler package need to be defined locally,
such as adding -g for the c_main.c source only, sharing can be
done at the
attribute level directly as in this new version of C_Main.Compiler:
package Compiler is
for Default_Switches ("C") use
Attribute_Sharing.Compiler'Default_Switches ("C");
for Switches ("c_main.c") use
Compiler'Default_Switches ("C") & ("-g");
end Compiler;
In order to change the compilation options of all C files used for
building both C_Main and Ada_Main, it is sufficient to edit a
single project file.
Previous sections have shown how to share both compilation units and project
properties
among different systems. Sharing is an essential aspect of large system
development since it avoids unnecessary duplication, reduces compilation time
and
lessens the maintenance burden. Unfortunately, it sometimes gets in the way.
In the above example, Ada_Main and C_Main both depend on
Common_Subsystems because they have precisely the same needs, but the
requirements of the two systems can diverge over time in which case
sharing becomes a problem rather than a solution. For instance,
suppose that C_Main is now baselined and should not be changed,
while Ada_Main is still under active development (which requires
changes in the sources of the common subsystem). The issue is how to satisfy
Ada_Main's needs without taking any risk of perturbing C_Main.
One
possibility is to duplicate the common subsystem completely so that one
version can evolve while the other one can remain frozen. That will force
duplication and recompilation of the whole project. Extensions provide a
more flexible mechanism, making it possible to provide a new version of
a subsystem without having to duplicate the sources that do not change.
A project extension inherits all the sources and objects from the project it
extends and allows you to redefine some of the sources which hide the original
versions. You can also add new sources or remove existing ones.
Here is an example of extending project Common_Subsystem:
project New_Common_Subsystem
extends "../subsystems/common_subsystem.gpr" is
for Source_Dirs use ("new_util_src");
for Object_Dir use "new_obj_util";
end New_Common_Subsystem;
The project sources are to be found in Common_Subsystem.Source_Dirs
and New_Common_Subsystem.Source_Dirs, the latter hiding the former
when the same source filenames are found in both. New sources can be
added to the project extension by simply placing them in its
Source_Dirs. Original sources can be removed, because of the attribute
Excluded_Source_Files.
When building a project extension, all units depending on new versions of
sources are rebuilt in the extension's Object_Dir. Other objects
remain in their original location and will be used by the builder whenever
necessary.
A project extension can be used in the context of a large program composed of many subsystems. Extending one subsystem may implicitly affect many other subsystems depending on it, even though there are no source changes in those dependent projects. In order to avoid the need to generate a project extension for each of the affected subsystems, you can use the notion of “extending all”, which basically means “extend all the projects necessary so that this specific project extension can be used instead of its original version”. Here is an example of an extending-all project:
with "new_common_subsystem.gpr";
project New_Ada_Main extends all "../subsystems/ada_main.gpr" is
for Source_Dirs use ("new_ada_src");
for Object_Dir use "new_obj";
for Exec_Dir use ".";
end New_Ada_Main;
A library is a subsystem packaged in a specific way. There are two
major kinds of libraries: static and dynamic. A project file
representing
a library is very similar to a project file representing a subsystem. You
just need to give the library a name, through the attribute
Library_Name. It is also possible to define a Library_Dir
which allows you to separate the final library components (e.g. archive files)
from the compilation byproducts (e.g. object files) that may be needed
to efficiently rebuild a new version of the library but which are not of any
interest to library users. Here is a simple project file for a static
library:
project Static_Lib is
for Languages use ("Ada", "C");
for Source_Dirs use ("lib_src");
for Object_Dir use "obj";
for Library_Dir use "lib";
for Library_Kind use "static";
for Library_Name use "l1";
end Static_Lib;
The library can be built on its own using standard GPRbuild commands, for example:
$gprbuild static_lib.gpr
It can also be built as a by product of building a main project using this library through a "with" as it was the case for simple subsystems:
with "static_lib.gpr";
project Main is
for Main use ("ada_main.adb");
end Main;
in which case
$gprbuild main.gpr
will rebuild the library l1 if it is not up to date.
To construct a dynamic library instead of a static library, simply replace
for Library_Kind use "static";
by
for Library_Kind use "dynamic";
Library projects can also be useful to describe a library that you may
want to use but that, for some reason, cannot be rebuilt,
for instance when the sources to rebuild the library are
not available. Such library projects need simply to use the
externally_built attribute as in the example below:
project Extern_Lib is
for Languages use ("Ada", "C");
for Source_Dirs use ("lib_src");
for Library_Dir use "lib2";
for Library_Kind use "dynamic";
for Library_Name use "l2";
for Externally_Built use "true";
end Extern_Lib;
In the case of externally built libraries, the Object_Dir
attribute does not need to be specified in this case because
it will never be used.
To be provided in a subsequent version of the document.
The following concepts are the foundation of GNAT Project files and the GPRbuild process.
A source file is associated with a language through a naming convention.
For instance, foo.c is typically
the name of a C source file; bar.ads or bar.1.ada are two
common naming conventions for a file containing an Ada spec.
A compilation unit is often composed of a main source file and potentially
several auxiliary ones, such as header files in C.
You can define or modify the naming conventions,
which are used by
GPRbuild to invoke the appropriate compiler.
Source files are looked up in the source directories associated with the
project through the Source_Dirs attribute. By default,
all the files (in these source directories) following the naming conventions
associated with the declared languages are
considered to be part of the project. It is also possible to limit the
list of source files using the Source_Files or
Source_List_File attributes.
An object file is an intermediate file produced by the compiler from a
compilation unit. It is used by the post-compilation phases to produce
final executables or libraries. The object files produced in the context of
a given project are stored in a single directory, the Object_Dir that
can
be specified in the project file. A need for storing
objects in different directories corresponds to the need to split the
system into distinct subsystems.
A text file using an Ada-like syntax. It defines build-related characteristics of an application, or a part of it. The characteristics include the list of sources, the location of those sources, the location for the generated object files, the name of the main program, and the default options for the various tools involved in the build process. These characteristics can be conditionalized through scenario variables and case statements.
A text file using the project file syntax. It defines languages and their characteristics as well as toolchains for those languages and their characteristics.
A specific characteristic as defined by a project attribute clause. Its
value is a string or a sequence of strings. For instance, the
Source_Dirs
attribute is a sequence of strings representing the actual names of the
directories containing the sources of the project. The attribute itself can
be parameterized. For instance Compiler'Default_Options ("Ada")
refers to the default compiler options for the Ada language.
Global characteristics are defined at the top level of a project.
Specific characteristics affecting a given tool are grouped in a
subpackage with the same name as the tool. The most common
subpackages are Builder, Compiler, Binder,
and Linker.
Two kinds of variables are available with projects: simple variables and
scenario variables. A simple variable can hold any string, or sequence of string
values; this is useful as a shortcut for a complex expression. Scenario
variables are a restricted version of simple variables; they can only take their
values from a static enumeration of strings representing the various
supported scenarios. These scenario variables are used in conjunction with
the case construct to offer limited conditionalization of
project characteristics. Both types of variables are local to the project
defining them and can get initialized with an external value, such as
an environment variable, through the external directive.
A subsystem is a coherent part of the complete system to be built. It
is represented by a set of sources and one object directory. A simple
system is composed of a single subsystem. Complex systems are usually
composed of a graph of interdependent subsystems. A subsystem is
dependent on another subsystem if knowledge of the other one is
required to build it, and in particular if visibility on some of the
sources of this other subsystem is required. A subsystem is usually
represented by one project file. The subsystem dependency relationship
is represented by the with clause between corresponding project
files.
A library is a specific type of subsystem where, for convenience, you group the objects together using system-specific means. Project files are a system- and language-independent way of building both static and dynamic libraries. They also support the concept of standalone libraries (SAL) which offers two significant properties: the initialization of the library is either automatic or very simple; a change in the implementation part of the library implies minimal post-compilation actions on the complete system and potentially no action at all for dynamic SALs.
A project extension is a project that represents an augmentation
of the original project. Suppose for instance that a
subsystem S is shared by two unrelated systems S1 and S2.
If S1 requires a
change in S, but this change would adversely affect S2,
then a modified version of S can be defined as an extension of
S, a “delta” to the original
version which only contains the new source files (those that have been
changed) and the objects that are affected by these changes.
Three elements can optionally be specified on GPRbuild's command line:
The general syntax is thus:
gprbuild [<proj>.gpr] [switches] [names]
{[-cargs opts] [-cargs:lang opts] [-largs opts] [-gargs opts]}
GPRbuild requires a project file, which may be specified on the command line, either directly or through the -P switch. If not specified, then GPRbuild uses the project file default.gpr if there is one in the current working directory. Otherwise, if there is only one project file in the current working directory, GPRbuild uses this project file.
Main source files represent the sources to be used as the main
programs. If they are not specified on the command line, GPRbuild uses
the source files specified with the Main attribute in the project
file. If none exists, then no executable will be built.
When source files are specified along with the option -c, then recompilation will be considered only for those source files. In all other cases, GPRbuild compiles or recompiles all sources in the project tree that are not up to date, and builds or rebuilds libraries that are not up to date.
If invoked without the --config= or --autoconf= options, then GPRbuild will look for a configuration project file default.cgpr, or <targetname>.cgpr if option --terget=<targetname> is used. If there is no such file in the default locations expected by GPRbuild (<install>/share/gpr and the current directory) then GPRbuild will invoke GPRconfig with the languages from the project files, and create a configuration project file auto.cgpr in the object directory of the main project. The project auto.cgpr will be rebuilt at each GPRbuild invocation unless you use the switch --autoconf=path/auto.cgpr, which will use the configuration project file if it exists and create it otherwise.
Options given on the GPRbuild command line may be passed along to individual tools by preceding them with one of the “command line separators” shown below. Options following the separator, up to the next separator (or end of the command line), are passed along. The different command line separators are:
The arguments that follow up to the next command line separator are options for all compilers for all languages. Example: -cargs -g
The arguments that follow up to the next command line separator are options for the compiler of the specific language.
Examples:
The arguments that follow up to the next command line separator are options for all binder drivers.
The arguments that follow up to the next command line separators are options for the binder driver of the specific language.
Examples:
The arguments that follow up to the next command line separator are options for the linker.
The arguments that follow up to the next command line separator are options for GPRbuild itself. Usually -gargs is specified after one or several other command line separators.
The switches that are interpreted directly by GPRbuild are:
Display information about GPRbuild: version, origin and legal status, then exit successfully, ignoring other options.
Display GPRbuild usage, then exit successfully, ignoring other options.
Display two lines: the configuration project file search path and the user project file search path, then exit successfully, ignoring other options.
This specifies the configuration project file name. By default, the configuration project file name is default.cgpr. Option --config= cannot be specified more than once. The configuration project file specified with --config= must exist.
This specifies a configuration project file name that already exists or will be created automatically. Option --autoconf= cannot be specified more than once. If the configuration project file specified with --autoconf= exists, then it is used. Otherwise, GPRconfig is invoked to create it automatically.
This specifies that the default configuration project file is <targetname>.cgpr. If no configuration project file with this name is found, then GPRconfig is invoked with option --target=<targetname>to create a configuration project file auto.cgpr.
Note: only one of --config, --autoconf or --target= can be specified.
Specify to GPRbuild to add directory dir to the user project file search path, before the default directory.
Specify to GPRbuild that the post-compilation (or binding) phase is to be performed, but not the other phases unless they are specified by appropriate switches.
Specify to GPRbuild that the compilation phase is to be performed, but not the other phases unless they are specified by appropriate switches.
Display progress for each source, up to date or not, as a single line completed x out of y (zz%).... If the file needs to be compiled this is displayed after the invocation of the compiler. These lines are displayed even in quiet output mode (switch -q).
By default, symbolic links are not taken into account to compute directories when processing project files. Switch -eL changes this default behavior.
Force the complete processing of all phases (or of those explicitly specified) even when up to date.
By default, in non verbose mode, when an error occurs while processing a project file, only the simple name of the project file is displayed in the error message. When switch -F is used, the full path of the project file is used. This switch has no effect when switch -v is used.
By default, GPRbuild invokes one compiler at a time. With switch -j, it is possible to instruct GPRbuild to spawn several simultaneous compilation jobs if needed. For example, -j2 for two simultaneous compilation jobs or -j4 for four.
By default, GPRbuild stops spawning new compilation jobs at the first compilation failure. Using switch -k, it is possible to attempt to compile/recompile all the sources that are not up to date, even when some compilations failed. The post-compilation phase and the linking phase are never attempted if there are compilation failures, even when switch -k is used.
Specify to GPRbuild that the linking phase is to be performed, but not the other phases unless they are specified by appropriate switches.
Specify the file name of a single executable. Switch -o cannot be
used with
several mains on the command line, nor with no main on the command line and
several mains in attribute Main of the main project.
By default, GPRbuild checks that the object, library and exec directories specified in project files exist. Switch -p instructs GPRbuild to attempt to create missing directories.
Specify the path name of the main project file. The space between -P and the project file name is optional. Specifying a project file name (with suffix .gpr) may be used in place of option -P. Exactly one main project file can be specified.
Do not display anything except errors and progress (switch -d). Cancel any previous switch -v.
By default, GPRbuild will not recompile a source if all dependencies are satisfied. Switch -s instructs GPRbuild to recompile sources when a different set of compilation switches has been used in the previous compilation, even if all dependencies are satisfied. Each time GPRbuild invokes a compiler, it writes a text file that lists the switches used in the invocation of the compiler, so that it can retrieve these switches if -s is used later.
If there are sources specified on the command line, only compile these sources. If there are no sources specified on the command line, compile all the sources of the main project.
In both cases, do not attempt the binding and the linking phases.
If there are sources specified on the command line, only compile these sources. If there are no sources specified on the command line, compile all the sources of all the projects in the project tree.
In both cases, do not attempt the binding and the linking phases.
Display full paths, all options used in spawned processes, and reasons why these processes are spawned. Cancel any previous switch -q.
By default, GPRbuild does not display anything when processing project files, except when there are errors. This default behavior is obtained with switch -vP0. Switches -vP1 and -vP2 yield increasingly detailed output.
When -we is used, any warning during the processing of the project files becomes an error and GPRbuild does not attempt any of the phases.
Switch -wn may be used to restore the default after -we or -ws.
Do not generate any warnings while processing the project files.
Specify an external reference that may be queried inside the project files
using built-in function external. For example, with
-XBUILD=DEBUG,
external("BUILD") inside a project file will have the value
"DEBUG".
Before performing one or several of its three phases, GPRbuild has to read the command line, obtain its configuration, and process the project files.
If GPRbuild is invoked with an invalid switch or without any project file on the command line, it will fail immediately.
Examples:
$ gprbuild -P
gprbuild: project file name missing after -P
$ gprbuild -P c_main.gpr -WW
gprbuild: illegal option "-WW"
GPRbuild looks for the configuration project file first in the current working directory, then in the default configuration project directory. If the GPRbuild executable is located in a subdirectory <prefix>/bin, then the default configuration project directory is <prefix>/share/gpr, otherwise there is no default configuration project directory.
When it has found its configuration project path, GPRbuild needs to obtain its configuration. By default, the file name of the main configuration project is default.cgpr. This default may be modified using the switch --config=...
Example:
$ gprbuild --config=my_standard.cgpr -P my_project.gpr
If GPRbuild cannot find the main configuration project on the configuration project path, then it will look for all the languages specified in the user project tree and invoke GPRconfig to create a configuration project file named auto.cgpr that is located in the object directory of the main project file.
Once it has found the configuration project, GPRbuild will process its configuration: if a single string attribute is specified in the configuration project and is not specified in a user project, then the attribute is added to the user project. If a string list attribute is specified in the configuration project then its value is prepended to the corresponding attribute in the user project.
After GPRbuild has processed its configuration, it will process the user project file or files. If these user project files are incorrect then GPRbuild will fail with the appropriate error messages:
$ gprbuild -P my_project.gpr
ada_main.gpr:3:26: "src" is not a valid directory
gprbuild: "my_project.gpr" processing failed
Once the user project files have been dealt with successfully, GPRbuild will start its processing.
If GPRbuild is invoked with -c and there are one or several source file names specified on the command line, GPRbuild will compile or recompile these sources, if they are not up to date or if -f is also specified. Then GPRbuild will stop its execution, even if -b or -l are specified.
The options/switches used to compile these sources are described in section Compilation Phase.
When switch -c is used or when switches -b or -l are not used, GPRbuild will first compile or recompile all the sources that are not up to date in all the projects in the project tree.
GPRbuild will first consider each source and decide if it needs to be (re)compiled.
A source needs to be compiled in the following cases:
When a source is successfully compiled, the following files are normally created in the object directory of the project of the source:
none
The compiler for the language of the source is invoked with the following switches/options:
Compiler of the
project of the source
If compilation is needed, then all the options/switches, except those described as “Various other options” are written to the switch file. The switch file is a text file. Its file name is obtained by replacing the suffix of the source with .cswi. For example, the switch file for source main.adb is main.cswi and for toto.c it is toto.cswi.
If the compilation is successful, then if the creation of the dependency
file is not done during compilation but after (see configuration attribute
Compute_Dependency), then the process to create the dependency file is
invoked.
If GPRbuild is invoked with a switch -j specifying more than one compilation process, then several compilation processes for several sources of possibly different languages are spawned concurrently.
To be provided in a subsequent version of the document.
To be provided in a subsequent version of the document.
The GPRclean tool removes the files created by GPRbuild.
At a minimum, to invoke GPRclean you must specify a main project file
in a command such as gprclean proj.gpr or gprclean -P proj.gpr.
Examples of invocation of GPRclean:
gprclean -r prj1.gpr
gprclean -c -P prj2.gpr
The switches for GPRclean are:
This specifies a configuration project file name that already exists or will be created automatically. Option --autoconf= cannot be specified more than once. If the configuration project file specified with --autoconf= exists, then it is used. Otherwise, GPRconfig is invoked to create it automatically.
The GPRconfig tool helps you generate the configuration files for GPRbuild. It automatically detects the available compilers on your system and, after you have selected the one needed for your application, it generates the proper configuration file.
--config and
--autoconf switches
GPRconfig supports the following command line switches:
This switch indicates the target computer on which your application will be run. It is mostly useful for cross configurations. Examples include ppc-elf, ppc-vx6-windows. It can also be used in native configurations and is useful when the same machine can run different kind of compilers such as mingw32 and cygwin on Windows or x86-32 and x86-64 on GNU Linux. Since different compilers will often return a different name for those targets, GPRconfig has an extensive knowledge of which targets are compatible, and will for example accept x86-linux as an alias for i686-pc-linux-gnu. The default target is the machine on which GPRconfig is run.
If you enter the special target all, then all compilers found on the
PATH will be displayed.
--target.
The intent of this switch is to preselect one or more compilers directly from the command line. This switch takes several optional arguments, which you can omit simply by passing the empty string. When omitted, the arguments will be computed automatically by GPRconfig.
In general, only language needs to be specified, and the first compiler on the PATH that can compile this language will be selected. As an example, for a multi-language application programmed in C and Ada, the command line would be:
--config=Ada --config=C
path is the directory that contains the compiler executable, for instance /usr/bin (and not the installation prefix /usr).
name should be one of the compiler names defined in the GPRconfig knowledge base. The list of supported names can be found in the output of -h, and includes GNAT, GCC,.... This name is generally not needed, but can be used to distinguish among several compilers that could match the other arguments of --config.
gprconfig --config Ada,,,/usr/bin # automatic parameters
gprconfig --config C,,,/usr/bin,GCC # automatic version
If this switch is specified, GPRconfig automatically selects the first
compiler matching each of the --config switches, and generates the
configuration file immediately. It will not display an interactive menu.
This specifies the name of the configuration file that will be generated.
If this switch is not specified, a default file is generated in the
installation directory of GPRbuild (assuming you have write access to
that directory), so that it is automatically picked up by GPRbuild later
on. If you select a different output file, you will need to specify it
to GPRbuild.
When you launch GPRconfig, it first searches for all compilers it can find on your PATH, that match the target specified by --target. It is recommended, although not required, that you place the compilers that you expect to use for your application in your PATH before you launch gprconfig, since that simplifies the setup.
GPRconfig then displays the list of all the compilers it has found, along with the language they can compile, the run-time they use (when applicable),.... It then waits for you to select one of the compilers. This list is sorted by language, then by order in the PATH environment variable (so that compilers that you are more likely to use appear first), then by run-time names and finally by version of the compiler. Thus the first compiler for any language is most likely the one you want to use.
You make a selection by entering the letter that appears on the line for each compiler (be aware that this letter is case sensitive). If the compiler was already selected, it is deselected.
A filtered list of compilers is then displayed: only compilers that target the same platform as the selected compiler are now shown. GPRconfig then checks whether it is possible to link sources compiled with the selected compiler and each of the remaining compilers; when linking is not possible, the compiler is not displayed. Likewise, all compilers for the same language are hidden, so that you can only select one compiler per language.
As an example, if you need to compile your application with several C compilers, you should create another language, for instance called C2, for that purpose. That will give you the flexibility to indicate in the project files which compiler should be used for which sources.
The goal of this filtering is to make it more obvious whether you have a good chance of being able to link. There is however no guarantee that GPRconfig will know for certain how to link any combination of the remaining compilers.
You can select as many compilers as are needed by your application. Once you have finished selecting the compilers, select <s>, and GPRconfig will generate the configuration file.
GPRconfig itself has no hard-coded knowledge of compilers. Thus there is no need to recompile a new version of GPRconfig when a new compiler is distributed.
All knowledge of compilers is embedded in a set of XML files called the knowledge base. Users can easily contribute to this general knowledge base, and have GPRconfig immediately take advantage of any new data.
The knowledge base contains various kinds of information:
When it is run interactively, GPRconfig searches the user's PATH for known compilers, and tries to deduce their configuration (version, supported languages, supported targets, run-times, ...). From the knowledge base GPRconfig knows how to extract the relevant information about a compiler.
This step is optional, since a user can also enter all the information manually. However, it is recommended that the knowledge base explicitly list its known compilers, to make configuration easier for end users.
When a compiler is used, depending on its version, target, run-time,..., some specific command line switches might have to be supplied. The knowledge base is a good place to store such information.
For instance, with the GNAT compiler, using the soft-float runtime should force gprbuild to use the -msoft-float compilation switch.
Linking a multi-language application often has some subtleties, and typically requires specific linker switches. These switches depend on the list of languages, the list of compilers,....
It is sometimes not possible to link together code compiled with two particular compilers. The knowledge base should store this information, so that end users are informed immediately when attempting to use such a compiler combination.
The end of this section will describe in more detail the format of this knowledge base, so that you can add your own information and have GPRconfig advantage of it.
The knowledge base is implemented as a set of XML files. None of these files has a special name, nor a special role. Instead, the user can freely create new files, and put them in the knowledge base directory, to contribute new knowledge.
The location of the knowledge base is $prefix/share/gprconfig, where $prefix is the directory in which GPRconfig was installed. Any file with extension .xml in this directory will be parsed automatically by GPRconfig at startup.
All files must have the following format:
<?xml version="1.0">
<gprconfig>
...
</gprconfig>
The root tag must be <gprconfig>.
The remaining sections in this chapter will list the valid XML tags that can be used to replace the “...” code above. These tags can either all be placed in a single XML files, or split across several files.
One of the XML tags that can be specified as a child of <gprconfig> is
<compiler_description>. This node and its children describe one of
the compilers known to GPRconfig. The tool uses them when it
initially looks for all compilers known on the user's PATH
environment variable.
This is optional information, but simplifies the use of GPRconfig, since the user is then able to omit some parameters from the --config command line argument, and have them automatically computed.
The <compiler_description> node doesn't accept any XML
attribute. However, it accepts a number of child tags that explain
how to query the various attributes of the compiler. The child tags
are evaluated (if necessary) in the same order as they are documented below.
<name>compiler_description node.
<compiler_description>
<name>GNAT</name>
</compiler_description>
<executable>In some cases, the tools have a common suffix, but a prefix that might depend
on the target. For instance, GNAT uses gnatmake for native platforms,
but powerpc-wrs-vxworks-gnatmake for cross-compilers to VxWorks.
Most of the compiler description is the same, however.
For such cases, the value of the executable node is considered as
beginning a regular expression. The tag also accepts an attribute prefix,
which is an integer indicating the parenthesis group that contains the prefix.
In the following example, you obtain the version of the GNAT compiler by running
either gnatls or powerpc-wrs-vxworks-gnatls, depending on
the name of the executable that was found.
The regular expression needs to match the whole name of the file, i.e. it contains an implicit “^” at the start, and an implicit “$” at the end. Therefore if you specify .*gnatmake as the regexp, it will not match gnatmake-debug.
<executable prefix="1">(powerpc-wrs-vxworks-)?gnatmake</executable>
<version><external>${PREFIX}gnatls -v</external></version>
GPRconfig searches in all directories listed on the PATH for such
an executable. When one is found, the rest of the <compiler_description>
children are checked to know whether the compiler is valid. The directory
in which the executable was found becomes the “current directory” for
the remaining XML children.
<target><version><variable name="varname"><languages>The value returned by the system will be split into words. As a result, if
the returned value is “ada,c,c++”, there are three languages supported by the
compiler (and three entries are added to the menu when using GPRconfig
interactively). The words can be comma-separated or space-separated.
<runtimes><languages>.
A number of the XML nodes described above can contain one or more children,
and specify how to query a value from an executable. Here is the list of
valid contents for these nodes. The <directory> and <external>
children can be repeated multiple times, and the <filter> and
<must_match> nodes will be applied to each of these. The final
value of the external value is the concatenation of the computation for each
of the <directory> and <external> nodes.
A simple string given in the node indicates a constant. For instance, the list of supported languages might be defined as:
<compiler_description>
<name>GNAT</name>
<executable>gnatmake</executable>
<languages>Ada</languages>
</compiler_description>
for the GNAT compiler, since this is an Ada-only compiler.
Variables can be referenced in simple strings.
<getenv name="variable" />
If the contents of the node is an <getenv> child, the value of
the environment variable variable is returned. If the variable is
not defined, this is an error and the compiler is ignored.
<compiler_description>
<name>GCC-WRS</name>
<executable prefix="1">cc(arm|pentium)</executable>
<version>
<getenv name="WIND_BASE" />
</version>
</compile_description>
<external>command</external>
If the contents of the node is an <external> child, this indicates
that a command should be run on the system.
When the command is run, the current directory (i.e., the one that contains
the executable found through the <executable> node, is placed first
on the PATH. The output of the command is returned and may be later
filtered. The command is not executed through a shell; therefore you cannot
use output redirection, pipes, or other advanced features.
For instance, extracting the target processor from gcc can be done with:
<version>
<external>gcc -dumpmachine</external>
</version>
Since the PATH has been modified, we know that the gcc command
that is executed is the one from the same directory as the <external>
node.
Variables are substituted in command.
<grep regexp="regexp" group="0" />
This node must come after the previously described ones. It is used to further filter the output. The previous output is matched against the regular expression regexp and the parenthesis group specified by group is returned. By default, group is 0, which indicates the whole output of the command.
For instance, extracting the version number from gcc can be done with:
<version>
<external>gcc -v</external>
<grep regexp="^gcc version (S+)" group="1" />
</version>
<directory group="0">regexp</directory>
If the contents of the node is a <directory> child, this
indicates that GPRconfig should find all the files matching the
regular expression. Regexp is a path relative to the directory that contains
the <executable> file, and should use unix directory separators
(ie '/'), since the actual directory will be converted into this format
before the match, for system independence of the knowledge base.
The group attribute indicates which parenthesis group should be returned. It defaults to 0 which indicates the whole matched path. If this attribute is a string rather than an integer, then it is the value returned.
regexp can be any valid regular expression. This will only match a directory name, not a subdirectory. Remember to quote special characters, including “.”, if you do not mean to use a regexp.
For instance, finding the list of supported runtimes for the GNAT compiler is done with:
<runtimes>
<directory group="1">
../lib/gcc/${TARGET}/.*/rts-(.*)/adainclude
</directory>
<directory group="default">
../lib/gcc/${TARGET}/.*/adainclude
</directory>
</runtimes>
Note the second node, which matches the default run-time, and displays it as such.
<filter>value1,value2,...</filter>
This node must come after one the previously described ones. It is used to further filter the output. The previous output is split into words (it is considered as a comma-separated or space-separated list of words), and only those words in value1, value2,... are kept.
For instance, the gcc compiler will return a variety of supported languages, including “ada”. If we do not want to use it as an Ada compiler we can specify:
<languages>
<external regexp="languages=(S+)" group="1">gcc -v</external>
<filter>c,c++,fortran</filter>
</languages>
<must_match>regexp</must_match>
If this node is present, then the filtered output is compared with the specified regular expression. If no match is found, then the executable is not stored in the list of known compilers.
For instance, if you want to have a <compiler_description> tag
specific to an older version of GCC, you could write:
<version>
<external regexp="gcc version (S+)"
group="1">gcc -v </external>
<must_match>2.8.1</must_match>
</version>
Other versions of gcc will not match this <compiler_description>
node.
The various compiler attributes defined above are made available as
variables in the rest of the XML files. Each of these variable can be used
in the value of the various nodes (for instance in <directory>),
and in the configurations (see Configuration).
A variable is referenced by ${name} where name is either
a user variable or a predefined variable. An alternate reference is
$name where name is a sequence of alpha numeric characters or
underscores. Finally $$ is replaced by a simple $.
User variables are defined by <variable> nodes and may override
predefined variables. To avoid a possible override use lower case names.
Predefined variables are always in upper case. Here is the list of predefined variables
<executable>. It
only contains the basename, not the directory information.
<target> node. This is of course not available when computing the
target itself.
<executable> node.
<executable>. It always ends with a directory separator.
RUNTIME_DIR always end with a directory separator.
If a variable is not defined, an error message is issued and the variable is substituted by an empty string.
The second type of information stored in the knowledge base are the chunks of gprbuild configuration files.
Each of these chunks is also placed in an XML node that provides optional filters. If all the filters match, then the chunk will be merged with other similar chunks and placed in the final configuration file that is generated by GPRconfig.
For instance, it is possible to indicate that a chunk should only be
included if the GNAT compiler with the soft-float runtime is used. Such
a chunk can for instance be used to ensure that Ada sources are always
compiled with the -msoft-float command line switch.
GPRconfig does not perform sophisticated merging of chunks. It simply groups packages together. For example, if the two chunks are:
chunk1:
package Language_Processing is
for Attr1 use ("foo");
end Language_Processing;
chunk2:
package Language_Processing is
for Attr1 use ("bar");
end Language_Processing;
Then the final configuration file will look like:
package Language_Processing is
for Attr1 use ("foo");
for Attr1 use ("bar");
end Language_Processing;
As a result, to avoid conflicts, it is recommended that the chunks be written so that they easily collaborate together. For instance, to obtain something equivalent to
package Language_Processing is
for Attr1 use ("foo", "bar");
end Language_Processing;
the two chunks above should be written as:
chunk1:
package Language_Processing is
for Attr1 use Language_Processing'Attr1 & ("foo");
end Language_Processing;
chunk2:
package Language_Processing is
for Attr1 use Language_Processing'Attr1 & ("bar");
end Language_Processing;
The chunks are described in a <configuration> XML node. The most
important child of such a node is <config>, which contains the
chunk itself. For instance, you would write:
<configuration>
... list of filters, see below
<config>
package Language_Processing is
for Attr1 use Language_Processing'Attr1 & ("foo");
end Language_Processing;
</config>
</configuration>
If <config> is an empty node (i.e., <config/> or
<config></config>) was used, then the combination of selected
compilers will be reported as invalid, in the sense that code
compiled with these compilers cannot be linked together. As a result,
GPRconfig will not create the configuration file.
The special variables (see GPRconfig variable substitution) are also substituted in the chunk. That allows you to compute some attributes of the compiler (its path, the runtime,...), and use them when generating the chunks.
The filters themselves are of course defined through XML tags, and can be any of:
<compilers negate="false"><compiler> children. The
<compilers> filter matches if any of its children match.
However, you can have several <compilers> filters, in which
case they must all match. This can be used to include linker switches
chunks. For instance, the following code would be used to describe
the linker switches to use when GNAT 5.05 or 5.04 is used in addition to
g++ 3.4.1:
<configuration>
<compilers>
<compiler name="GNAT" version="5.04" />
<compiler name="GNAT" version="5.05" />
</compilers>
<compilers>
<compiler name="G++" version="3.4.1" />
</compilers>
...
</configuration>
If the attribute negate is true, then the meaning of this filter is inverted, and it will match if none of its children matches.
The format of the <compiler> is the following:
<compiler name="name" version="..."
runtime="..." language="..." />
The name and language attributes, when specified, match
the corresponding attributes used in the <compiler_description>
children. All other attributes are regular expressions, which are matched
against the corresponding selected compilers. When an attribute is not
specified, it will always match. Matching is done in a case-insensitive
manner.
For instance, to check a GNAT compiler in the 5.x family, use:
<compiler name="GNAT" version="5.d+" />
<hosts negate="false"><host> children. It matches when
any of its children matches. You can specify only one <hosts>
node.
The format of <host> is a node with a single mandatory attribute
name, which is a regexp matched against the architecture on
which GPRconfig is running. The name of the architecture was
computed by configure when GPRconfig was built.
If the negate attribute is true, then the meaning of this filter is inverted, and it will match when none of its children matches.
For instance, to active a chunk only if the compiler is running on an intel linux machine, use:
<hosts>
<host name="i.86-.*-linux(-gnu)?" />
</hosts>
<targets negate="false"><target> children. It behaves
exactly like <hosts>, but matches against the architecture
targeted by the selected compilers. For instance, to activate a chunk
only when the code is targeted for linux, use:
If the negate attribute is true, then the meaning of this filter is inverted, and it will match when none of its children matches.
<targets>
<target name="i.86-.*-linux(-gnu)?" />
</targets>
GPRbuild needs to have a configuration file to know the different characteristics of the toolchains that can be used to compile sources and build libraries and executables.
A configuration file is a special kind of project file: it uses the same syntax as a standard project file. Attributes in the configuration file define the configuration. Some of these attributes have a special meaning in the configuration.
The default name of the configuration file, when not specified to GPRbuild by switches –config= or –autoconf= is default.cgpr. Although the name of the configuration file can be any valid file name, it is recommended that its suffix be .cgpr (for Configuration GNAT Project), so that it cannot be confused with a standard project file which has the suffix .gpr.
When default.cgpr cannot be found in the configuration project path, GPRbuild invokes GPRconfig to create a configuration file.
In the following description of the attributes, when an attribute is an
associative array indexed by the language name, for example
Spec_Suffix (<language>), then the name of the language is case insensitive.
For example, both C and c are allowed.
Any attribute may appear in a configuration project file. All attributes in a configuration project file are inherited by each user project file in the project tree. However, usually only the attributes listed below make sense in the configuration project file.
Specifies the name of the language of the immediate sources of a project when
attribute Languages is not declared in the project. If attribute
Default_Language is not declared in the configuration file, then each user
project file in the project tree must have an attribute Languages declared,
unless it extends another project. Example:
for Default_Language use "ada";
Specifies a “run path option”; i.e., an option to use when linking an executable or a shared library to indicate the path where to look for other libraries. The value of this attribute is a string list. When linking an executable or a shared library, the search path is concatenated with the last string in the list, which may be an empty string. Example:
for Run_Path_Option use ("-Wl,-rpath,");
Specifies a version for a toolchain, as a single string. This toolchain version is passed to the library builder. Example:
for Toolchain_Version ("Ada") use "GNAT 6.1";
This attribute is used by GPRbind to decide on the names of the shared GNAT runtime libraries.
Specifies as a single string a description of a toolchain. This attribute is not directly used by GPRbuild or its auxiliary tools (GPRbind and GPRlib) but may be used by other tools, for example GPS. Example:
for Toolchain_Description ("C") use "gcc version 4.1.3 20070425";
Specifies the level of support for library project. If this attribute is not
specified, then library projects are not supported. The only potential values
for this attribute are none, static_only and full. Example:
for Library_Support use "full";
Specifies the name of the executable for the library builder. Example:
for Library_Builder use "/.../gprlib";
Specifies the name of the executable of the archive builder with the minimum options, if any. Example:
for Archive_Builder use ("ar", "cr");
Specifies the name of the executable of the archive indexer with the minimum options, if any. If this attribute is not specified, then there is no archive indexer. Example:
for Archive_Indexer use ("ranlib");
Specifies the suffix of the archives. If this attribute is not specified, then the suffix of the archives is defaulted to .a. Example:
for Archive_Suffix use ".olb"; -- for VMS
Specifies the name of the executable of the partial linker with the options to be used, if any. If this attribute is not specified, then there is no partial linking. Example:
for Library_Partial_Linker use ("gcc", "-nostdlib", "-Wl,-r", "-o");
Specifies the prefix of the file names of shared libraries. When this attribute
is not specified, the prefix is lib. Example:
for Shared_Library_Prefix use ""; -- for Windows, if needed
Specifies the suffix of the file names of shared libraries. When this attribute is not specified, the suffix is .so. Example:
for Shared_Library_Suffix use ".dll"; -- for Windows
Specifies if symbolic links are supported by the platforms. The possible values
of this attribute are "false" (the default) and "true". When this attribute is
not specified, symbolic links are not supported.
for Symbolic_Link_Supported use "true";
Specifies if major and minor IDs are supported for shared libraries.
The possible values of this attribute are "false" (the default) and "true".
When this attribute is not specified, major and minor IDs are not supported.
for Library_Major_Minor_ID_Supported use "True";
Specifies if library auto initialization is supported. The possible values of
this attribute are "false" (the default) and "true". When this attribute is not
specified, library auto initialization is not supported.
for Library_Auto_Init_Supported use "true";
Specifies the minimum options to be used when building shared library. These options are put in the appropriate section in the library exchange file when the library builder is invoked. Example:
for Shared_Library_Minimum_Switches use ("-shared");
Specifies the option or options to be used when a library version is used. These options are put in the appropriate section in the library exchange file when the library builder is invoked. Example:
for Library_Version_Switches use ("-Wl,-soname,");
Specifies the directory for the runtime libraries for the language. Example:
for Runtime_Library_Dir ("Ada") use "/path/to/adalib";
This attribute is used by GPRlib to link shared libraries with Ada code.
Attributes in package Naming of a configuration file specify defaults. These
attributes may be used in user project files to replace these defaults.
The following attributes usually appear in package Naming of a configuration
file:
Specifies the default suffix for a “spec” or header file. Examples:
for Spec_Suffix ("Ada") use ".ads";
for Spec_Suffix ("C") use ".h";
for Spec_Suffix ("C++") use ".hh";
Specifies the default suffix for a “body” or a source file. Examples:
for Body_Suffix ("Ada") use ".adb";
for Body_Suffix ("C") use ".c";
for Body_Suffix ("C++") use ".cpp";
Specifies the suffix for a subunit source file (separate) in Ada. If attribute
Separate_Suffix is not specified, then the default suffix of subunit source
files is the same as the default suffix for body source files. Example:
for Separate_Suffix use ".sep";
Specifies the casing of spec and body files in a unit based language
(such as Ada) to know how to map a unit name to its file name. The values for
this attribute may only be "lowercase", "UPPERCASE" and "Mixedcase".
The default, when attribute Casing is not specified is lower case.
This attribute rarely needs to be specified, since on
platforms where file names are not case sensitive (such as Windows or VMS)
the default (lower case) will suffice.
Specifies the string to replace a dot (“.”) in unit names of a unit based
language (such as Ada) to obtain its file name. If there is any unit based
language in the configuration, attribute Dot_Replacement must be declared.
Example:
for Dot_Replacement use "-";
Specifies the default executable suffix. If no attribute Executable_Suffix is
declared, then the default executable suffix for the host platform is used.
Example:
for Executable_Suffix use ".exe";
Specifies the name of the executable for the compiler of a language. The single string value of this attribute may be an absolute path or a relative path. If relative, then the execution path is searched. Examples:
for Driver ("C++") use "g++";
for Driver ("Ada") use "/.../bin/gcc";
Specifies the minimum options that must be used when invoking the compiler of a language. Examples:
for Required_Switches ("C") use ("-c", "-x", "c");
for Required_Switches ("Ada") use ("-c", "-x", "ada", "-gnatA");
Specifies the option or options that must be used when compiling a source of a language to be put in a shared library. Example:
for PIC_Option ("C") use ("-fPIC");
Specifies the switch or switches to be used to specify a mapping file to the
compiler. When attribute Mapping_File_Switches is not declared, then no
mapping file is specified to the compiler. The value of this attribute is a
string list. The path name of the mapping file is concatenated with the last
string in the string list, which may be empty. Example:
for Mapping_File_Switches ("Ada") use ("-gnatem=");
Specifies, for unit based languages that support mapping files, the suffix in the mapping file that needs to be added to the unit name for specs. Example:
for Mapping_Spec_Suffix ("Ada") use "%s";
Specifies, for unit based languages that support mapping files, the suffix in the mapping file that needs to be added to the unit name for bodies. Example:
for Mapping_Spec_Suffix ("Ada") use "%b";
In the value of config file attributes defined below, there are some placeholders that GPRbuild will replace. These placeholders are:
Attributes:
Specifies the switch or switches to be used to specify a configuration file to
the compiler. When attribute Config_File_Switches is not declared, then no
config file is specified to the compiler. The value of this attribute is a
string list. The path name of the config file is concatenated with the last
string in the string list, which may be empty. Example:
for Config_File_Switches ("Ada") use ("-gnatec=");
Specifies the line to be put in a config file to indicate the file name of a body. Example:
for Config_Body_File_Name ("Ada") use
"pragma Source_File_Name_Project (%u, Body_File_Name => ""%f"");";
Specifies the line to be put in a config file to indicate the file name of a spec. Example:
for Config_Spec_File_Name ("Ada") use
"pragma Source_File_Name_Project (%u, Spec_File_Name => ""%f"");";
Specifies the line to be put in a config file to indicate a body file name pattern. Example:
for Config_Body_File_Name_Pattern ("Ada") use
"pragma Source_File_Name_Project " &
" (Body_File_Name => ""*%b""," &
" Casing => %c," &
" Dot_Replacement => ""%d"");";
Specifies the line to be put in a config file to indicate a spec file name pattern. Example:
for Config_Spec_File_Name_Pattern ("Ada") use
"pragma Source_File_Name_Project " &
" (Spec_File_Name => ""*%s""," &
" Casing => %c," &
" Dot_Replacement => ""%d"");";
Specifies, for languages that support config files, if several config files
may be indicated to the compiler, or not. This attribute may have only two
values: "true" or "false" (case insensitive). The default, when this attribute
is not specified, is "false". When the value "true" is specified for this
attribute, GPRbuild will concatenate the config files, if there are more than
one. Example:
for Config_File_Unique ("Ada") use "True";
There are two dependency-related attributes: Dependency_Switches and
Dependency_Driver. If neither of these two attributes are specified for
a language other than Ada, then the source needs to be (re)compiled if
the object file does not exist or the source file is more recent than
the object file or the switch file.
For languages other than Ada, attribute Dependency_Switches specifies
the option or options to add to the compiler invocation so that it creates
the dependency file at the same time. The value of attribute Dependency_Option
is a string list. The name of the dependency file is added to the last string
in the list, which may be empty. Example:
for Dependency_Switches ("C") use ("-Wp,-MD,");
With these Dependency_Switches, when compiling file.c the compiler will be
invoked with the option -Wp,-MD,file.d.
Specifies the command and options to create a dependency file for a source. The full path name of the source is appended to the last string of the string list value. Example:
for Dependency_Driver ("C") use ("gcc", "-E", "-Wp,-M", "");
Usually, attributes Dependency_Switches and Dependency_Driver are not both
specified.
Specifies the option or options to use when invoking the compiler to indicate that a directory is part of the source search path. The value of this attribute is a string list. The full path name of the directory is concatenated with the last string in the string list, which may be empty. Example:
for Include_Switches ("C") use ("-I");
Attribute Include_Switches is ignored if either one of the attributes
Include_Path or Include_Path_File are specified.
Specifies the name of an environment variable that is used by the compiler to get the source search path. The value of the environment variable is the source search path to be used by the compiler. Example:
for Include_Path ("C") use "CPATH";
for Include_Path ("Ada") use "ADA_INCLUDE_PATH";
Attribute Include_Path is ignored if attribute Include_Path_File is declared
for the language.
Specifies the name of an environment variable that is used by the compiler to get the source search path. The value of the environment variable is the path name of a text file that contain the path names of the directories of the source search path. Example:
for Include_Path_File ("Ada") use "ADA_PRJ_INCLUDE_FILE";
Specifies the name of the executable of the binder driver. When this attribute is not specified, there is no binder for the language. Example:
for Driver ("Ada") use "/.../gprbind";
Specifies the minimum options to be used when invoking the binder driver. These options are put in the appropriate section in the binder exchange file, one option per line. Example:
for Required_Switches ("Ada") use ("--prefix=<prefix>");
Specifies the prefix to be used in the name of the binder exchange file. Example:
for Prefix ("C++") use ("c__");
Specifies the name of an environment variable that is used by the compiler to get the object search path. The value of the environment variable is the object search path to be used by the compiler. Example:
for Objects_Path ("Ada") use "ADA_OBJECTS_PATH";
Specifies the name of an environment variable that is used by the compiler to get the object search path. The value of the environment variable is the path name of a text file that contain the path names of the directories of the object search path. Example:
for Objects_Path_File ("Ada") use "ADA_PRJ_OBJECTS_FILE";
Specifies the name of the executable of the default linker. Example:
for Driver use "g++";
Specifies the minimum options to be used when invoking the default linker.