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
UPPERorLOWER. 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
UPPERorLOWER. 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
UPPERorLOWER. 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
UPPERorLOWER.
Module Functions¶
-
FortranCInterface_HEADER¶ The
FortranCInterface_HEADERfunction 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>. SYMBOLSList 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
SYMBOLSoption with a given namespace<ns>.
- Global symbols without ‘_’:
-
FortranCInterface_VERIFY¶ The
FortranCInterface_VERIFYfunction 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(orFortranCInterface_VERIFIED_CXXifCXXis given) as a boolean. If the check fails andQUIETis 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 theReleaseconfiguration.
Example Usage¶
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_().
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:
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.)