[Bug c++/13687] New: -Wmissing-prototypes should not be ignored for C++

["t dot schutter at att dot net" <gcc-bugzilla at gcc dot gnu dot org>]

Currently, -Wmissing-prototypes is ignored when compiling C++ code.  I believe
that this is because it is assumed that missing prototypes are errors when
compiling C++ code.  This is true, except when using the extern "C" { }
construct.  When using this construct, you should be able to get "no previous
prototype" warnings.

This problem is most evident when using the JNI native interface which uses the
extern "C" { } construct.  Prototype/function mismatches are not found until
runtime.

The following example shows the problem:

/*
  Compiling as C gives a warning:
  $ gcc -c -Wmissing-prototypes gccbug.c
  gccbug.c:19: warning: no previous prototype for `bar'
  $

  Compiling as C++ gives no warning:
  $ g++ -c -Wmissing-prototypes gccbug.c
  $
*/

#ifdef __cplusplus
extern "C" {
#endif

void foo(void);
void foo(void) { }

void bar(void) { }

#ifdef __cplusplus
}
#endif

-- 
           Summary: -Wmissing-prototypes should not be ignored for C++
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: t dot schutter at att dot net
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13687