[cups] cupsdStartProcess question

[Dmitry Voronin]

Hello,

For my reasons in CUPS I need execute external program and save output into file.

I determine, that function cupsdStartProcess is more suitable, that system or exec* function.

So, I have following code:

outfd = open('/tmp/exec", O_WRONLY);

status = cupsdStartProcess(command, argv, envp,
                                         -1 /* intfd */,
                                          outfd /* opened early */,
                                          -1 /* errfd */,
                                          -1 /* backfd */,
                                          -1 /* sidefd */,
                                          1 /* execute as root */,
                                          NULL /* profile */,
                                          NULL /*job */,
                                          &pid /* running pid */);

if (!status)
  close(outfd);
else
{
  close(outfd);
  unlink("/tmp/exec");
 }

When those code is executed, I expect, that in file with fd outfd it was written output of my command. But those file is empty. In /var/spool/cups/tmp/ (I use Debian)
CUPS create a random file with neede for me output.

What am I doing wrong?

Thank you.
-- 
Best regards, Dmitry Voronin