Paul Edwards wrote in a message to All:

 PE> /* Anyone know why this program gets a link error if
 PE> compiled    with Watcom C++ 10.0B for OS/2 */
 PE>    
 PE> #include 
 PE> #include 

 PE> int main(void)
 PE> {
 PE>     int x;
 PE>     
 PE>     x = _osmode;
 PE>     printf("x is %d\n", x);
 PE>     return (0);
 PE> }

This has significance only in 16-bit programs and is set in the startup
code by a call to DosGetMachineMode(), which exists only in the 16-bit OS/2
API. Obviously, if your 32-bit OS/2 program is running, you are in
protected mode.

The only real purpose for _osmode is in bound programs written mostly to
the Family API.  By checking _osmode, you can use certain features only
accessible in one mode or the other, or which have to be done differently
depending upon mode.  For example, if you wanted a FAPI program to be
mouse-aware, you would need to check _osmode at run time and call either
the DOS Int 33h or OS/2 Mou subsystem, as appropriate.

If what you want to know is whether your code is going through the 16-bit
or 32-bit compiler at compile time, check for the "M_I86" or
"M_I386" predefined macro.  If you want to know whether your code
is being compiled for DOS or OS/2, check for the "__DOS__" or
"__OS2__" predefined macros.

While "__DOS__" and "__OS2__" are Watcom-specific,
"M_I386" is used in IBM's OS2.H header, so any 32-bit OS/2
compiler can be counted upon to predefine it. If it is defined, OS2.H
defines "INCL_32" or otherwise defines "INCL_16", and
it is safe to use these once OS2.H has itself been included.

If you really are writing a FAPI program, you will see "M_I86"
and "__OS2__" defined.  Watcom does not come with a complete set
of tools for FAPI, and you will have to get BIND.EXE and API.LIB from the
OS/2 1.3 Toolkit (on DevCon).
 
-- Mike


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