This is the mail archive of the
gcc-help@gcc.gnu.org
mailing list for the GCC project.
Warning for incompatible functions declared 'extern "C"'?
- From: Nick <nospam at codesniffer dot com>
- To: gcc-help <gcc-help at gcc dot gnu dot org>
- Date: Wed, 23 Jul 2014 18:53:09 -0400
- Subject: Warning for incompatible functions declared 'extern "C"'?
- Authentication-results: sourceware.org; auth=none
I have an oversight in my code where I'm declaring & defining a function
with C-linkage, though it's not possible.
Example snippet:
<snip>
//------------------------------------------------------------
#ifdef __cplusplus
extern "C"
{
#endif
// ... some functions which are compatible with C linkage
// Intended to be a helper function not exposed from library
std::string GetEngineVersion()
{
// ...
}
#ifdef __cplusplus
}
#endif
//------------------------------------------------------------
</snip>
Obviously the GetEngineVersion function cannot have C linkage because it
returns a C++ class.
My question is: does GCC have a warning for this scenario?
Specifically, can it warn when something is declared extern "C" that's
incompatible with C linkage?
I compile with the following warning flags and I didn't get a warning:
-Wall -Wunused-parameter -Wextra -Weffc++ -Wctor-dtor-privacy
-Wnon-virtual-dtor -Wreorder -Wold-style-cast -Woverloaded-virtual
-Werror
Incidentally, when I compile the same code in VS2013 I get this warning:
warning C4190: 'GetEngineVersion' has C-linkage specified, but returns
UDT
'std::basic_string<char,std::char_traits<char>,std::allocator<char>>'
which is incompatible with C
Best regards,
Nick