Thread: return value from main()

The FAQ has a detailed description of spawn() and family, and it uses process.h. http://faq.cprogramming.com/cgi-bin/...&id=1043284392

Try searching your header files, I'm sure that one of them has "spawn". I think that some systems use posix_spawn_something().

The Wikipedia entry has lots of information about spawn(): http://en.wikipedia.org/wiki/Spawn_%28computer%29

Try unistd.h: http://en.wikipedia.org/wiki/Exec_%2...ting_system%29

Originally Posted by megastar

but i think the part where you try to do
iRet=system(szProgram);
the RETURN VALUE OF THE SYSTEM NEED NOT BE THE RETURN VALUE OF PROGRAM.

Indeed, quite correct.

Originally Posted by megastar

This was according to the link given by zacs7.

This was also given in my post in this topic:

Originally Posted by MacGyver

rv can indeed be the return value of the program. Whether it is or not depends upon other factors, such as whether or not the command you ran was actually able to be executed or not.

This matches what you discovered:

Originally Posted by megastar

I also ran your 3rd program and i was getting the output 32512 on passing
the name of any file.
http://www.cplusplus.com/reference/c...ib/system.html

I found this having to do with ruby, but I find the return value interesting. More googling indicates that the value 32512 is a value that can be obtained from system().

Originally Posted by megastar

Any suggestions?

I did warn that the programs I provided are proof of concept, and while I would encourage people to experiment, to be prepared for this. They naturally worked for me, but I have little confidence in system()'s portability in this regard since it relies heavily on the behavior of O/S-specific shells, and I admit I know not much about the underlying mechanisms for most systems.