DOS ain't dead - C's system() & COMMAND.COM

C's system() & COMMAND.COM (Developers)

posted by alexfru, USA, 13.09.2014, 01:05

> FWIW:
>
> I looked up the system() function in my copy of K&R 2nd edition, and it
> says
>
> "In the UNIX system, the status return is the value returned by exit"
>
> Further it says "the return value is implementation-dependent".

Check out some more modern stuff.

http://pubs.opengroup.org/onlinepubs/009695399/functions/system.html:

"
If command is not a null pointer, system() shall return the termination status of the command language interpreter in the format specified by waitpid(). The termination status shall be as defined for the sh utility; ...
"

http://pubs.opengroup.org/onlinepubs/009695399/functions/waitpid.html:

"
The value stored at the location pointed to by stat_loc shall be 0 if and only if the status returned is from a terminated child process that terminated by one of the following means:

The process returned 0 from main().

The process called _exit() or exit() with a status argument of 0.

The process was terminated because the last thread in the process terminated.
"

http://pubs.opengroup.org/onlinepubs/009695399/utilities/sh.html:

"
The following exit values shall be returned:

0
The script to be executed consisted solely of zero or more blank lines or comments, or both.
1-125
A non-interactive shell detected a syntax, redirection, or variable assignment error.
127
A specified command_file could not be found by a non-interactive shell.

Otherwise, the shell shall return the exit status of the last command it invoked or attempted to invoke...
"

I can reasonably expect to get 0 from system() on POSIX systems if the command has succeeded (main() returned with 0) and non-zero otherwise.

Alex

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Complete thread:

C's system() & COMMAND.COM - alexfru, 11.09.2014, 21:26
- C's system() & COMMAND.COM - nidud, 11.09.2014, 23:22
  - C's system() & COMMAND.COM - alexfru, 12.09.2014, 02:55
    - C's system() & COMMAND.COM - nidud, 12.09.2014, 12:44
      - C's system() & COMMAND.COM - alexfru, 13.09.2014, 00:54
        C's system() & COMMAND.COM - nidud, 13.09.2014, 14:54
    - C's system() & COMMAND.COM - tom, 12.09.2014, 13:10
      - C's system() & COMMAND.COM - marcov, 12.09.2014, 20:00
        C's system() & COMMAND.COM - alexfru, 13.09.2014, 01:05
        C's system() & COMMAND.COM - marcov, 13.09.2014, 14:02
        C's system() & COMMAND.COM - alexfru, 13.09.2014, 14:21
        C's system() & COMMAND.COM - marcov, 13.09.2014, 16:50
        C's system() & COMMAND.COM - alexfru, 13.09.2014, 17:06
        C's system() & COMMAND.COM - marcov, 13.09.2014, 20:24
        C's system() & COMMAND.COM - alexfru, 16.09.2014, 23:27
        C's system() & COMMAND.COM - marcov, 17.09.2014, 13:03
        C's system() & COMMAND.COM - alexfru, 17.09.2014, 13:07
        C's system() & COMMAND.COM - bretjohn, 15.09.2014, 19:24
        C's system() & COMMAND.COM - alexfru, 16.09.2014, 23:24
        C's system() & COMMAND.COM - marcov, 17.09.2014, 13:04
        C's system() & COMMAND.COM - alexfru, 17.09.2014, 13:08
        C's system() & COMMAND.COM - bretjohn, 17.09.2014, 20:42
        C's system() & COMMAND.COM - alexfru, 17.09.2014, 22:53
        C's system() & COMMAND.COM - marcov, 18.09.2014, 12:18
        C's system() & COMMAND.COM - alexfru, 18.09.2014, 13:33
        C's system() & COMMAND.COM - Rugxulo, 18.09.2014, 15:20
        C's system() & COMMAND.COM - alexfru, 18.09.2014, 15:41
        C's system() & COMMAND.COM - Rugxulo, 01.11.2014, 23:48
        C's system() & COMMAND.COM - Rugxulo, 02.11.2014, 00:29
        C's system() & COMMAND.COM - marcov, 18.09.2014, 16:10
        C's system() & COMMAND.COM - marcov, 18.09.2014, 16:07
        C's system() & COMMAND.COM - Rugxulo, 18.09.2014, 07:27
        C's system() & COMMAND.COM - bretjohn, 18.09.2014, 18:14
        C's system() & COMMAND.COM - Rugxulo, 01.11.2014, 23:32
      - C's system() & COMMAND.COM - alexfru, 13.09.2014, 01:00