This example retrieves the process identity from a queue by passing the queue handle to WinQueryQueueInfo.

#define INCL_WINMESSAGEMGR
#include <OS2.H>

HMQ    hmq;
MQINFO mqinfo;
PID    pid;

WinQueryQueueInfo(hmq,
                  &mqinfo,
                  sizeof(MQINFO));

pid = mqinfo.pid;