This function creates a message queue.

#define INCL_WINMESSAGEMGR /* Or use INCL_WIN, INCL_PM, Also in COMMON section */
#include <os2.h>

HAB     hab;         /*  Anchor-block handle. */
LONG    lQueuesize;  /*  Maximum queue size. */
HMQ     hmq;         /*  Message-queue handle. */

hmq = WinCreateMsgQueue(hab, lQueuesize);