c++/7646: Inclusion of X11 header files in to a C++ header, causes error messages during compilation.

[marcusma@lsl.co.uk]

>Number:         7646
>Category:       c++
>Synopsis:       Inclusion of X11 header files in to a C++ header, causes error messages during compilation.
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Aug 20 03:06:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Marcus MacWilliam
>Release:        gcc v3.1
>Organization:
>Environment:
Solaris 8, running on a SparcUltra 10.
>Description:
The following example code from Xlib.h:

extern XSetTransientForHint(
#if NeedFunctionPrototypes
    Display*            /* display */,
    Window              /* w */,
    Window              /* prop_window */
#endif
);

causes the following error during compilation:

/usr/openwin/include/X11/Xlib.h:2099: ISO C++ forbids declaration of `
   XSetTransientForHint' with no type

What would be useful, is a compiler flag that allows headers
to be treated as C headers, not C++. It is imperative that the
X11 headers can be included, and that the C++ compiles.
>How-To-Repeat:
Create a file DummyX11.cpp with the following:

#include <X11/Xlib.h>
#include <stdio>

int main () {
    cout << "Hello" << endl;
}

Compile with the following:

g++ -I/usr/openwin/include DummyX11.cpp.

This will produce the errors.
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: