Re: Server writing: observations and questions

[Roland McGrath]

The GNU `error' function is good for this; see <error.h>.  It is takes a
printf format, but also takes an argument that if non-zero is an exit code
(if zero it does not exit) and an argument that if non-zero is an errno
code to print after the formatted message (and a colon).  So do:

  err = mach_msg (...);
  if (err)
    {
      error (0, err, "mach_msg %s", "blah");
      return 1;
    }

or if you want to just die:

  err = mach_msg (...);
  if (err)
    error (1, err, "mach_msg %s", "blah");

It will print:

program: mach_msg blah: error string

to stderr.