POSIX system() call return value

My question is simple, but I guess the answer isn't. Why does the
system() function on a POSIX system return the exit status of the
called command as 2^8*n instead of n?

Any good replies much appreciated,

Jens Thiede.

re: POSIX system() call return value

jensthiede@gmail.com wrote:Because system() itself might fail, and if the exit status of the called
command was n, there is no way of knowing if system() has failed, of the
called command.



Igmar

re: POSIX system() call return value

Igmar Palsenberg wrote:Thanks, that makes sense.

Jens.

re: POSIX system() call return value

Igmar Palsenberg wrote:Which is why, if you check your system's documentation, you will
probably see it tell you which macros to use to decode the value.

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re: POSIX system() call return value

jensthiede@gmail.com writes:The C standard says only:

If the argument is a null pointer, the system function returns
nonzero only if a command processor is available. If the argument
is not a null pointer, and the system function does return, it
returns an implementation-defined value.

If you have specific questions about POSIX (which is not part of the C
standard), try comp.unix.programmer -- or consult the documentation
for your system.

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