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# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
#[=======================================================================[.rst:
FortranCInterface
-----------------
Fortran/C Interface Detection
This module automatically detects the API by which C and Fortran
languages interact.
Module Variables
^^^^^^^^^^^^^^^^
Variables that indicate if the mangling is found:
``FortranCInterface_GLOBAL_FOUND``
Global subroutines and functions.
``FortranCInterface_MODULE_FOUND``
Module subroutines and functions (declared by "MODULE PROCEDURE").
This module also provides the following variables to specify
the detected mangling, though a typical use case does not need
to reference them and can use the `Module Functions`_ below.
``FortranCInterface_GLOBAL_PREFIX``
Prefix for a global symbol without an underscore.
``FortranCInterface_GLOBAL_SUFFIX``
Suffix for a global symbol without an underscore.
``FortranCInterface_GLOBAL_CASE``
The case for a global symbol without an underscore,
either ``UPPER`` or ``LOWER``.
``FortranCInterface_GLOBAL__PREFIX``
Prefix for a global symbol with an underscore.
``FortranCInterface_GLOBAL__SUFFIX``
Suffix for a global symbol with an underscore.
``FortranCInterface_GLOBAL__CASE``
The case for a global symbol with an underscore,
either ``UPPER`` or ``LOWER``.
``FortranCInterface_MODULE_PREFIX``
Prefix for a module symbol without an underscore.
``FortranCInterface_MODULE_MIDDLE``
Middle of a module symbol without an underscore that appears
between the name of the module and the name of the symbol.
``FortranCInterface_MODULE_SUFFIX``
Suffix for a module symbol without an underscore.
``FortranCInterface_MODULE_CASE``
The case for a module symbol without an underscore,
either ``UPPER`` or ``LOWER``.
``FortranCInterface_MODULE__PREFIX``
Prefix for a module symbol with an underscore.
``FortranCInterface_MODULE__MIDDLE``
Middle of a module symbol with an underscore that appears
between the name of the module and the name of the symbol.
``FortranCInterface_MODULE__SUFFIX``
Suffix for a module symbol with an underscore.
``FortranCInterface_MODULE__CASE``
The case for a module symbol with an underscore,
either ``UPPER`` or ``LOWER``.
Module Functions
^^^^^^^^^^^^^^^^
.. command:: FortranCInterface_HEADER
The ``FortranCInterface_HEADER`` function is provided to generate a
C header file containing macros to mangle symbol names::
FortranCInterface_HEADER(<file>
[MACRO_NAMESPACE <macro-ns>]
[SYMBOL_NAMESPACE <ns>]
[SYMBOLS [<module>:]<function> ...])
It generates in ``<file>`` definitions of the following macros::
#define FortranCInterface_GLOBAL (name,NAME) ...
#define FortranCInterface_GLOBAL_(name,NAME) ...
#define FortranCInterface_MODULE (mod,name, MOD,NAME) ...
#define FortranCInterface_MODULE_(mod,name, MOD,NAME) ...
These macros mangle four categories of Fortran symbols, respectively:
* Global symbols without '_': ``call mysub()``
* Global symbols with '_' : ``call my_sub()``
* Module symbols without '_': ``use mymod; call mysub()``
* Module symbols with '_' : ``use mymod; call my_sub()``
If mangling for a category is not known, its macro is left undefined.
All macros require raw names in both lower case and upper case.
The options are:
``MACRO_NAMESPACE``
Replace the default ``FortranCInterface_`` prefix with a given
namespace ``<macro-ns>``.
``SYMBOLS``
List symbols to mangle automatically with C preprocessor definitions::
<function> ==> #define <ns><function> ...
<module>:<function> ==> #define <ns><module>_<function> ...
If the mangling for some symbol is not known then no preprocessor
definition is created, and a warning is displayed.
``SYMBOL_NAMESPACE``
Prefix all preprocessor definitions generated by the ``SYMBOLS``
option with a given namespace ``<ns>``.
.. command:: FortranCInterface_VERIFY
The ``FortranCInterface_VERIFY`` function is provided to verify
that the Fortran and C/C++ compilers work together::
FortranCInterface_VERIFY([CXX] [QUIET])
It tests whether a simple test executable using Fortran and C (and C++
when the CXX option is given) compiles and links successfully. The
result is stored in the cache entry ``FortranCInterface_VERIFIED_C``
(or ``FortranCInterface_VERIFIED_CXX`` if ``CXX`` is given) as a boolean.
If the check fails and ``QUIET`` is not given the function terminates with a
fatal error message describing the problem. The purpose of this check
is to stop a build early for incompatible compiler combinations. The
test is built in the ``Release`` configuration.
Example Usage
^^^^^^^^^^^^^
.. code-block:: cmake
include(FortranCInterface)
FortranCInterface_HEADER(FC.h MACRO_NAMESPACE "FC_")
This creates a "FC.h" header that defines mangling macros ``FC_GLOBAL()``,
``FC_GLOBAL_()``, ``FC_MODULE()``, and ``FC_MODULE_()``.
.. code-block:: cmake
include(FortranCInterface)
FortranCInterface_HEADER(FCMangle.h
MACRO_NAMESPACE "FC_"
SYMBOL_NAMESPACE "FC_"
SYMBOLS mysub mymod:my_sub)
This creates a "FCMangle.h" header that defines the same ``FC_*()``
mangling macros as the previous example plus preprocessor symbols
``FC_mysub`` and ``FC_mymod_my_sub``.
Additional Manglings
^^^^^^^^^^^^^^^^^^^^
FortranCInterface is aware of possible ``GLOBAL`` and ``MODULE`` manglings
for many Fortran compilers, but it also provides an interface to specify
new possible manglings. Set the variables::
FortranCInterface_GLOBAL_SYMBOLS
FortranCInterface_MODULE_SYMBOLS
before including FortranCInterface to specify manglings of the symbols
``MySub``, ``My_Sub``, ``MyModule:MySub``, and ``My_Module:My_Sub``.
For example, the code:
.. code-block:: cmake
set(FortranCInterface_GLOBAL_SYMBOLS mysub_ my_sub__ MYSUB_)
# ^^^^^ ^^^^^^ ^^^^^
set(FortranCInterface_MODULE_SYMBOLS
__mymodule_MOD_mysub __my_module_MOD_my_sub)
# ^^^^^^^^ ^^^^^ ^^^^^^^^^ ^^^^^^
include(FortranCInterface)
tells FortranCInterface to try given ``GLOBAL`` and ``MODULE`` manglings.
(The carets point at raw symbol names for clarity in this example but
are not needed.)
#]=======================================================================]
#-----------------------------------------------------------------------------
# Execute at most once in a project.
if(FortranCInterface_SOURCE_DIR)
return()
endif()
cmake_policy(PUSH)
cmake_policy(SET CMP0007 NEW)
#-----------------------------------------------------------------------------
# Verify that C and Fortran are available.
foreach(lang C Fortran)
if(NOT CMAKE_${lang}_COMPILER_LOADED)
message(FATAL_ERROR
"FortranCInterface requires the ${lang} language to be enabled.")
endif()
endforeach()
#-----------------------------------------------------------------------------
set(FortranCInterface_SOURCE_DIR ${CMAKE_ROOT}/Modules/FortranCInterface)
# MinGW's make tool does not always like () in the path
if("${CMAKE_GENERATOR}" MATCHES "MinGW" AND
"${FortranCInterface_SOURCE_DIR}" MATCHES "[()]")
file(COPY ${FortranCInterface_SOURCE_DIR}/
DESTINATION ${CMAKE_BINARY_DIR}/CMakeFiles/FortranCInterfaceMinGW)
set(FortranCInterface_SOURCE_DIR ${CMAKE_BINARY_DIR}/CMakeFiles/FortranCInterfaceMinGW)
endif()
# Create the interface detection project if it does not exist.
if(NOT FortranCInterface_BINARY_DIR)
set(FortranCInterface_BINARY_DIR ${CMAKE_BINARY_DIR}/CMakeFiles/FortranCInterface)
include(${FortranCInterface_SOURCE_DIR}/Detect.cmake)
endif()
# Load the detection results.
include(${FortranCInterface_BINARY_DIR}/Output.cmake)
#-----------------------------------------------------------------------------
function(FortranCInterface_HEADER file)
# Parse arguments.
if(IS_ABSOLUTE "${file}")
set(FILE "${file}")
else()
set(FILE "${CMAKE_CURRENT_BINARY_DIR}/${file}")
endif()
set(MACRO_NAMESPACE "FortranCInterface_")
set(SYMBOL_NAMESPACE)
set(SYMBOLS)
set(doing)
foreach(arg ${ARGN})
if("x${arg}" MATCHES "^x(SYMBOLS|SYMBOL_NAMESPACE|MACRO_NAMESPACE)$")
set(doing "${arg}")
elseif("x${doing}" MATCHES "^x(SYMBOLS)$")
list(APPEND "${doing}" "${arg}")
elseif("x${doing}" MATCHES "^x(SYMBOL_NAMESPACE|MACRO_NAMESPACE)$")
set("${doing}" "${arg}")
set(doing)
else()
message(AUTHOR_WARNING "Unknown argument: \"${arg}\"")
endif()
endforeach()
# Generate macro definitions.
set(HEADER_CONTENT)
set(_desc_GLOBAL "/* Mangling for Fortran global symbols without underscores. */")
set(_desc_GLOBAL_ "/* Mangling for Fortran global symbols with underscores. */")
set(_desc_MODULE "/* Mangling for Fortran module symbols without underscores. */")
set(_desc_MODULE_ "/* Mangling for Fortran module symbols with underscores. */")
foreach(macro GLOBAL GLOBAL_ MODULE MODULE_)
if(FortranCInterface_${macro}_MACRO)
string(APPEND HEADER_CONTENT "
${_desc_${macro}}
#define ${MACRO_NAMESPACE}${macro}${FortranCInterface_${macro}_MACRO}
")
endif()
endforeach()
# Generate symbol mangling definitions.
if(SYMBOLS)
string(APPEND HEADER_CONTENT "
/*--------------------------------------------------------------------------*/
/* Mangle some symbols automatically. */
")
endif()
foreach(f ${SYMBOLS})
if("${f}" MATCHES ":")
# Module symbol name. Parse "<module>:<function>" syntax.
string(REPLACE ":" ";" pieces "${f}")
list(GET pieces 0 module)
list(GET pieces 1 function)
string(TOUPPER "${module}" m_upper)
string(TOLOWER "${module}" m_lower)
string(TOUPPER "${function}" f_upper)
string(TOLOWER "${function}" f_lower)
if("${function}" MATCHES "_")
set(form "_")
else()
set(form "")
endif()
if(FortranCInterface_MODULE${form}_MACRO)
string(APPEND HEADER_CONTENT "#define ${SYMBOL_NAMESPACE}${module}_${function} ${MACRO_NAMESPACE}MODULE${form}(${m_lower},${f_lower}, ${m_upper},${f_upper})\n")
else()
message(AUTHOR_WARNING "No FortranCInterface mangling known for ${f}")
endif()
else()
# Global symbol name.
if("${f}" MATCHES "_")
set(form "_")
else()
set(form "")
endif()
string(TOUPPER "${f}" f_upper)
string(TOLOWER "${f}" f_lower)
if(FortranCInterface_GLOBAL${form}_MACRO)
string(APPEND HEADER_CONTENT "#define ${SYMBOL_NAMESPACE}${f} ${MACRO_NAMESPACE}GLOBAL${form}(${f_lower}, ${f_upper})\n")
else()
message(AUTHOR_WARNING "No FortranCInterface mangling known for ${f}")
endif()
endif()
endforeach()
# Store the content.
configure_file(${FortranCInterface_SOURCE_DIR}/Macro.h.in ${FILE} @ONLY)
endfunction()
function(FortranCInterface_VERIFY)
# Check arguments.
set(lang C)
set(quiet 0)
set(verify_cxx 0)
foreach(arg ${ARGN})
if("${arg}" STREQUAL "QUIET")
set(quiet 1)
elseif("${arg}" STREQUAL "CXX")
set(lang CXX)
set(verify_cxx 1)
else()
message(FATAL_ERROR
"FortranCInterface_VERIFY - called with unknown argument:\n ${arg}")
endif()
endforeach()
if(NOT CMAKE_${lang}_COMPILER_LOADED)
message(FATAL_ERROR
"FortranCInterface_VERIFY(${lang}) requires ${lang} to be enabled.")
endif()
# Build the verification project if not yet built.
if(NOT DEFINED FortranCInterface_VERIFIED_${lang})
set(_desc "Verifying Fortran/${lang} Compiler Compatibility")
message(STATUS "${_desc}")
# Build a sample project which reports symbols.
set(CMAKE_TRY_COMPILE_CONFIGURATION Release)
try_compile(FortranCInterface_VERIFY_${lang}_COMPILED
${FortranCInterface_BINARY_DIR}/Verify${lang}
${FortranCInterface_SOURCE_DIR}/Verify
VerifyFortranC # project name
VerifyFortranC # target name
CMAKE_FLAGS -DVERIFY_CXX=${verify_cxx}
-DCMAKE_VERBOSE_MAKEFILE=ON
"-DCMAKE_C_FLAGS:STRING=${CMAKE_C_FLAGS}"
"-DCMAKE_CXX_FLAGS:STRING=${CMAKE_CXX_FLAGS}"
"-DCMAKE_Fortran_FLAGS:STRING=${CMAKE_Fortran_FLAGS}"
"-DCMAKE_C_FLAGS_RELEASE:STRING=${CMAKE_C_FLAGS_RELEASE}"
"-DCMAKE_CXX_FLAGS_RELEASE:STRING=${CMAKE_CXX_FLAGS_RELEASE}"
"-DCMAKE_Fortran_FLAGS_RELEASE:STRING=${CMAKE_Fortran_FLAGS_RELEASE}"
OUTPUT_VARIABLE _output)
file(WRITE "${FortranCInterface_BINARY_DIR}/Verify${lang}/output.txt" "${_output}")
# Report results.
if(FortranCInterface_VERIFY_${lang}_COMPILED)
message(STATUS "${_desc} - Success")
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeOutput.log
"${_desc} passed with the following output:\n${_output}\n\n")
set(FortranCInterface_VERIFIED_${lang} 1 CACHE INTERNAL "Fortran/${lang} compatibility")
else()
message(STATUS "${_desc} - Failed")
file(APPEND ${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/CMakeError.log
"${_desc} failed with the following output:\n${_output}\n\n")
set(FortranCInterface_VERIFIED_${lang} 0 CACHE INTERNAL "Fortran/${lang} compatibility")
endif()
unset(FortranCInterface_VERIFY_${lang}_COMPILED CACHE)
endif()
# Error if compilers are incompatible.
if(NOT FortranCInterface_VERIFIED_${lang} AND NOT quiet)
file(READ "${FortranCInterface_BINARY_DIR}/Verify${lang}/output.txt" _output)
string(REPLACE "\n" "\n " _output "${_output}")
message(FATAL_ERROR
"The Fortran compiler:\n ${CMAKE_Fortran_COMPILER}\n"
"and the ${lang} compiler:\n ${CMAKE_${lang}_COMPILER}\n"
"failed to compile a simple test project using both languages. "
"The output was:\n ${_output}")
endif()
endfunction()
# Restore including context policies.
cmake_policy(POP)