This example creates a MuxWait semaphore, adding two event semaphores to its record list at creation time. Then, it shows how to open it. Some return code checking has been omitted for brevity.

#define INCL_DOSSEMAPHORES   /* DOS semaphore values */
#define INCL_DOSERRORS       /* DOS error values */
#include <os2.h>
#include <stdio.h>

int main(VOID) {
 HMUX       hmuxFromCreate  = NULLHANDLE;   /* Handle returned by Create */
 HMUX       hmuxFromOpen    = NULLHANDLE;   /* Handle returned by Open */
 HEV        hev[2]          = {0};          /* Event semaphores */
 SEMRECORD  apsr[2]         = {{0}};        /* Semaphore records */
 APIRET     rc              = NO_ERROR;     /* Return code */
 ULONG      ulSem           = 0;

rc = DosCreateEventSem("\\SEM32\\E0", &hev[0], 0, FALSE);
apsr[0].hsemCur = (HSEM) hev[0],
apsr[0].ulUser = 0;

rc = DosCreateEventSem("\\SEM32\\E1", &hev[1], 0, FALSE);
apsr[1].hsemCur = (HSEM) hev[1],
apsr[1].ulUser = 0;

rc = DosCreateMuxWaitSem("\\SEM32\\MUXWAIT1", &hmuxFromCreate, 2L,
                         apsr, DCMW_WAIT_ALL);
if (rc != NO_ERROR) {
   printf("DosCreateMuxWaitSem error:  return code = %u\n", rc);
   return 1;
} else {
   printf ("DosCreateMuxWaitSem returns handle = 0x%x\n", hmuxFromCreate);
}
      /*******************************************************************/
      /* The following call would normally be done from another program. */
      /*******************************************************************/

rc = DosOpenMuxWaitSem("\\SEM32\\MUXWAIT1",
                        &hmuxFromOpen);     /* Handle returned */
if (rc != NO_ERROR) {
  printf("DosOpenMuxWaitSem error:  return code = %u\n", rc);
  return 1;
} else {
   printf ("DosOpenMuxWaitSem   returns handle = 0x%x\n", hmuxFromOpen);
}

return NO_ERROR;
}