This example creates a muxwait semaphore with two event semaphores in its list, queries the number of entries, and displays it.

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

int main(VOID) {
 HMUX       hmuxHandAny  = NULLHANDLE;   /* Muxwaithandle */
 HEV        hev[2]       = {0};          /* Event semaphores */
 SEMRECORD  apsr[2]      = {{0}};        /* Semaphore records */
 SEMRECORD  semrecQuery[2] = {{0}};        /* Pointer from query */
 ULONG      cQueryRec    = 2;            /* Number of records found by query */
 ULONG      fQueryFlags  = 0;            /* Attribute flags returned by query */
 APIRET     rc           = NO_ERROR;     /* Return code */
 ULONG      ulLoop       = 0;            /* Loop count */
 ULONG      ulSem        = 0;

for (ulLoop = 0; ulLoop < 2; ulLoop++) {
    rc = DosCreateEventSem((PSZ) NULL, &hev[ulLoop], 0, FALSE);
    if (rc != NO_ERROR) {
      printf("DosCreateEventSem error:  return code = %u\n", rc);
      return 1;
    }
    apsr[ulLoop].hsemCur = (HSEM) hev[ulLoop],
    apsr[ulLoop].ulUser = 0;
} /* endfor */

rc = DosCreateMuxWaitSem((PSZ) NULL, &hmuxHandAny, 2L, apsr, DCMW_WAIT_ANY);
if (rc != NO_ERROR) {
   printf("DosCreateMuxWaitSem error:  return code = %u\n", rc);
   return 1;
}
           /* Query information about the MuxWait semaphore */

rc = DosQueryMuxWaitSem(hmuxHandAny,    /* Semaphore handle */
                        &cQueryRec,     /* Number of records */
                        (PSEMRECORD) semrecQuery,  /* Pointer to Semrecords */
                        &fQueryFlags);  /* Flags returned */
if (rc != NO_ERROR) {
  printf("DosQueryMuxWaitSem error:  return code = %u\n", rc);
  return 1;
} else {
  printf("DosQueryMuxWaitSem found %u semaphore records\n", cQueryRec);
} /* endif */

return NO_ERROR;
}