[TUHS] why the leading under score added to function names?

[random832@fastmail.us (Random832)]

I'm going to need to train myself to use the "reply to list" button. 
Though in this case I think part of the problem was duplicate-filtering 
which lost the copy that had the appropriate header.

On 2/25/2012 3:39 PM, John Cowan wrote:
>  Random832 scripsit:
>
>>  For instance, this is, according to Raymond Chen, why they added
>>  WinMain rather than extending main (they didn't know if extensions to
>>  main would be allowed).
>  That doesn't sound very reasonable to me.  When you link a Windows
>  program, it still has a main() procedure provided by Windows which does
>  setup and then invokes WinMain().

This is not true in my experience. If it was ever true, it's not true
today (with MSVC, anyway. GCC may be different, but if there is a
'system-provided main()' it's GCC, or cygwin or mingw, and not anything
from microsoft, that is providing it). The procedure "provided by
windows" (provided by MSVC, actually) that does that is in fact called
WinMainCRTStartup. When you link a windows _console_ program, a
different function (called mainCRTStartup) which does the same setup
(plus opening a console if none is open and setting up stdio which the
WinMain version doesn't) and then invokes main().

The startup function is an interesting read - it has more work to do on
windows than the unix equivalent, because systems like signals (which
are in ANSI), file descriptor based I/O (which is not ANSI but
nevertheless is implemented in MSVC), and such, that are "naturally
occuring" on unix have to be set up. The whole program executes in a
__try/__except block to allow them to make signals work, for example.