This option will generate C prototypes from BIND(C) variable
declarations, types and procedure interfaces and writes them to
standard output. ENUM is not yet supported.
The generated prototypes may need inclusion of an appropriate header,
such as <stdint.h> or <stdlib.h>. For types which are
not specified using the appropriate kind from the iso_c_binding
module, a warning is added as a comment to the code.
For function pointers, a pointer to a function returning int
without an explicit argument list is generated.
Example of use:
$ gfortran -fc-prototypes -fsyntax-only foo.f90 > foo.h
where the C code intended for interoperating with the Fortran code
then uses #include "foo.h".
This option will generate C prototypes from external functions and
subroutines and write them to standard output. This may be useful for
making sure that C bindings to Fortran code are correct. This option
does not generate prototypes for BIND(C) procedures, use
-fc-prototypes for that.
The generated prototypes may need inclusion of an appropriate
header, such as as <stdint.h> or <stdlib.h>.
This is primarily meant for legacy code to ensure that existing C
bindings match what gfortran emits. The generated C
prototypes should be correct for the current version of the compiler,
but may not match what other compilers or earlier versions of
gfortran need. For new developments, use of the
BIND(C) features is recommended.
Example of use:
$ gfortran -fc-prototypes-external -fsyntax-only foo.f > foo.h
where the C code intended for interoperating with the Fortran code
then uses #include "foo.h".