UseSWIG

This file provides support for SWIG. It is assumed that FindSWIG module has already been loaded.

Defines the following command for use with SWIG:

swig_add_library

Define swig module with given name and specified language:

swig_add_library(<name>
                 [TYPE <SHARED|MODULE|STATIC|USE_BUILD_SHARED_LIBS>]
                 LANGUAGE <language>
                 [NO_PROXY]
                 [OUTPUT_DIR <directory>]
                 [OUTFILE_DIR <directory>]
                 SOURCES <file>...
                )

Targets created with the swig_add_library command have the same capabilities as targets created with the add_library() command, so those targets can be used with any command expecting a target (e.g. target_link_libraries()).

Note

This command creates a target with the specified <name> when policy CMP0078 is set to NEW. Otherwise, the legacy behavior will choose a different target name and store it in the SWIG_MODULE_<name>_REAL_NAME variable.

Note

For multi-config generators, this module does not support configuration-specific files generated by SWIG. All build configurations must result in the same generated source file.

TYPE
SHARED, MODULE and STATIC have the same semantic as for the add_library() command. If USE_BUILD_SHARED_LIBS is specified, the library type will be STATIC or SHARED based on whether the current value of the BUILD_SHARED_LIBS variable is ON. If no type is specified, MODULE will be used.
LANGUAGE
Specify the target language.
NO_PROXY
Prevent the generation of the wrapper layer (swig -noproxy option).
OUTPUT_DIR

Specify where to write the language specific files (swig -outdir option). If not given, the CMAKE_SWIG_OUTDIR variable will be used. If neither is specified, the default depends on the value of the UseSWIG_MODULE_VERSION variable as follows:

  • If UseSWIG_MODULE_VERSION is 1 or is undefined, output is written to the CMAKE_CURRENT_BINARY_DIR directory.
  • If UseSWIG_MODULE_VERSION is 2, a dedicated directory will be used. The path of this directory can be retrieved from the SWIG_SUPPORT_FILES_DIRECTORY target property.
OUTFILE_DIR
Specify an output directory name where the generated source file will be placed (swig -o option). If not specified, the SWIG_OUTFILE_DIR variable will be used. If neither is specified, OUTPUT_DIR or CMAKE_SWIG_OUTDIR is used instead.
SOURCES
List of sources for the library. Files with extension .i will be identified as sources for the SWIG tool. Other files will be handled in the standard way.

Note

If UseSWIG_MODULE_VERSION is set to 2, it is strongly recommended to use a dedicated directory unique to the target when either the OUTPUT_DIR option or the CMAKE_SWIG_OUTDIR variable are specified. The output directory contents are erased as part of the target build, so to prevent interference between targets or losing other important files, each target should have its own dedicated output directory.

Link libraries to swig module:

swig_link_libraries(<name> <item>...)

This command has same capabilities as target_link_libraries() command.

Note

If variable UseSWIG_TARGET_NAME_PREFERENCE is set to STANDARD, this command is deprecated and target_link_libraries() command must be used instead.

Source file properties on module files must be set before the invocation of the swig_add_library command to specify special behavior of SWIG and ensure generated files will receive the required settings.

CPLUSPLUS

Call SWIG in c++ mode. For example:

set_property(SOURCE mymod.i PROPERTY CPLUSPLUS ON)
swig_add_library(mymod LANGUAGE python SOURCES mymod.i)
INCLUDE_DIRECTORIES, COMPILE_DEFINITIONS and COMPILE_OPTIONS
Add custom flags to SWIG compiler and have same semantic as properties INCLUDE_DIRECTORIES, COMPILE_DEFINITIONS and COMPILE_OPTIONS.
USE_TARGET_INCLUDE_DIRECTORIES
If set to TRUE, contents of target property INCLUDE_DIRECTORIES will be forwarded to SWIG compiler. If set to FALSE target property INCLUDE_DIRECTORIES will be ignored. If not set, target property SWIG_USE_TARGET_INCLUDE_DIRECTORIES will be considered.
GENERATED_INCLUDE_DIRECTORIES, GENERATED_COMPILE_DEFINITIONS and GENERATED_COMPILE_OPTIONS
Add custom flags to the C/C++ generated source. They will fill, respectively, properties INCLUDE_DIRECTORIES, COMPILE_DEFINITIONS and COMPILE_OPTIONS of generated C/C++ file.
DEPENDS
Specify additional dependencies to the source file.
SWIG_MODULE_NAME

Specify the actual import name of the module in the target language. This is required if it cannot be scanned automatically from source or different from the module file basename. For example:

set_property(SOURCE mymod.i PROPERTY SWIG_MODULE_NAME mymod_realname)

Target library properties can be set to apply same configuration to all SWIG input files.

SWIG_INCLUDE_DIRECTORIES, SWIG_COMPILE_DEFINITIONS and SWIG_COMPILE_OPTIONS

These properties will be applied to all SWIG input files and have same semantic as target properties INCLUDE_DIRECTORIES, COMPILE_DEFINITIONS and COMPILE_OPTIONS.

set (UseSWIG_TARGET_NAME_PREFERENCE STANDARD)
swig_add_library(mymod LANGUAGE python SOURCES mymod.i)
set_property(TARGET mymod PROPERTY SWIG_COMPILE_DEFINITIONS MY_DEF1 MY_DEF2)
set_property(TARGET mymod PROPERTY SWIG_COMPILE_OPTIONS -bla -blb)
SWIG_USE_TARGET_INCLUDE_DIRECTORIES
If set to TRUE, contents of target property INCLUDE_DIRECTORIES will be forwarded to SWIG compiler. If set to FALSE or not defined, target property INCLUDE_DIRECTORIES will be ignored. This behavior can be overridden by specifying source property USE_TARGET_INCLUDE_DIRECTORIES.
SWIG_GENERATED_INCLUDE_DIRECTORIES, SWIG_GENERATED_COMPILE_DEFINITIONS and SWIG_GENERATED_COMPILE_OPTIONS
These properties will populate, respectively, properties INCLUDE_DIRECTORIES, COMPILE_DEFINITIONS and COMPILE_FLAGS of all generated C/C++ files.
SWIG_DEPENDS
Add dependencies to all SWIG input files.

The following target properties are output properties and can be used to get information about support files generated by SWIG interface compilation.

SWIG_SUPPORT_FILES

This output property list of wrapper files generated during SWIG compilation.

set (UseSWIG_TARGET_NAME_PREFERENCE STANDARD)
swig_add_library(mymod LANGUAGE python SOURCES mymod.i)
get_property(support_files TARGET mymod PROPERTY SWIG_SUPPORT_FILES)

Note

Only most principal support files are listed. In case some advanced features of SWIG are used (for example %template), associated support files may not be listed. Prefer to use the SWIG_SUPPORT_FILES_DIRECTORY property to handle support files.

SWIG_SUPPORT_FILES_DIRECTORY
This output property specifies the directory where support files will be generated.

Some variables can be set to customize the behavior of swig_add_library as well as SWIG:

UseSWIG_MODULE_VERSION

Specify different behaviors for UseSWIG module.

  • Set to 1 or undefined: Legacy behavior is applied.
  • Set to 2: A new strategy is applied regarding support files: the output directory of support files is erased before SWIG interface compilation.
CMAKE_SWIG_FLAGS
Add flags to all swig calls.
CMAKE_SWIG_OUTDIR
Specify where to write the language specific files (swig -outdir option).
SWIG_OUTFILE_DIR
Specify an output directory name where the generated source file will be placed. If not specified, CMAKE_SWIG_OUTDIR is used.
SWIG_MODULE_<name>_EXTRA_DEPS
Specify extra dependencies for the generated module for <name>.