MFC requires C++ compilation (use a .cpp suffix) ????

[Vinod]

Hi I have some code in .c and and some in .cpp which uses MFC. I am getting
following error "fatal error C1189: #error : MFC requires C++ compilation
(use a .cpp suffix)" in My ".c" files. I am including a ".h" header file
which has "#include stdafx.h" . If I remove this "#include stdafx.h" from
header compilation and linking is fine. I cannot rename my .c file to .cpp
. Since there are some callback functions which are in .cpp files called
by .c files, I am having this problem. Please suggest me what can I do to
resolve this problem.

Thanks,
Vinod

[ralph]

"Vinod" <vkushwaha@hotmail.com> wrote:
>
>Hi I have some code in .c and and some in .cpp which uses MFC. I am getting
>following error "fatal error C1189: #error : MFC requires C++ compilation
>(use a .cpp suffix)" in My ".c" files. I am including a ".h" header file
>which has "#include stdafx.h" . If I remove this "#include stdafx.h" from
>header compilation and linking is fine. I cannot rename my .c file to .cpp
>. Since there are some callback functions which are in .cpp files called
>by .c files, I am having this problem. Please suggest me what can I do to
>resolve this problem.
>
>Thanks,
>Vinod
>

A compiler directive which will soon become your friend -> extern "C"

The compiler will automatically compile your 'c' modules (.c) as "C" code
and .cpp files as "C++" code. The problem comes in telling the c++ about
the c-function in the c-modules with the c-headers. You do that by telling
the cpp compiler/linker that the linkage specification for these functions
are "C".

You need to bracket the C code/function/headers with the extern "C" directive.

<Out of the Manual>
C++ uses the same calling convention and parameter-passing techniques as
C, but naming conventions are different because of C++ decoration of external
symbols. By causing C++ to drop name decoration, the extern "C" syntax makes
it possible for a C++ module to share data and routines with other languages.

The following example declares prn as an external function using the C naming
convention. This declaration appears in C++ source code.

extern "C"
{
void prn();
}

and or

extern "C"
{
#include "myCFile.h"
}

This will solve the problem for most situations.

It was my intention to send you the URL for Mixed-Language Programming but
M$ has moved stuff on their site around and I can't find it. If you have
your MSDN disk do a search for "Mixed-Language Programming".