re PR fortran/45435 (Automatically generate C interop interface blocks from C code)

[gcc.git] / gcc / fortran / invoke.texi

diff --git a/gcc/fortran/invoke.texi b/gcc/fortran/invoke.texi
index 8a1d09dd5e524c394d7370405373d855daba3ad5..15fdc16028a541d080820fef61547814a0d5e2a9 100644 (file)
--- a/gcc/fortran/invoke.texi
+++ b/gcc/fortran/invoke.texi
@@ -100,6 +100,8 @@ one is not the default.
 * Runtime Options::     Influencing runtime behavior
 * Code Gen Options::    Specifying conventions for function calls, data layout
                         and register usage.
+* Interoperability Options::  Options for interoperability with other
+                              languages.
 * Environment Variables:: Environment variables that affect @command{gfortran}.
 @end menu
 
@@ -171,6 +173,10 @@ and warnings}.
 -frecord-marker=@var{length} -fsign-zero
 }
 
+@item Interoperability Options
+@xref{Interoperability Options,,Options for interoperability}.
+@gccoptlist{-fc-prototypes}
+
 @item Code Generation Options
 @xref{Code Gen Options,,Options for code generation conventions}.
 @gccoptlist{-faggressive-function-elimination -fblas-matmul-limit=@var{n} @gol
@@ -1746,6 +1752,34 @@ shared by @command{gfortran}, @command{gcc}, and other GNU compilers.
 
 @c man end
 
+@node Interoperability Options
+@section Options for interoperability with other languages
+
+@table @asis
+
+@item -fc-prototypes
+@opindex @code{c-prototypes}
+@cindex Generating C prototypes from Fortran source code
+This option will generate C prototypes from @code{BIND(C)} variable
+declarations, types and procedure interfaces and writes them to
+standard output.  @code{ENUM} is not yet supported.
+
+The generated prototypes may need inclusion of an appropriate header,
+such as @code{<stdint.h>} or @code{<stdlib.h>}.  For types which are
+not specified using the appropriate kind from the @code{iso_c_binding}
+module, a warning is added as a comment to the code.
+
+For function pointers, a pointer to a function returning @code{int}
+without an explicit argument list is generated.
+
+Example of use:
+@smallexample
+$ gfortran -fc-prototypes -fsyntax-only foo.f90 > foo.h
+@end smallexample
+where the C code intended for interoperating with the Fortran code
+then  uses @code{#include "foo.h"}.
+@end table
+
 @node Environment Variables
 @section Environment variables affecting @command{gfortran}
 @cindex environment variable