DosAddMuxWaitSem

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DosAddMuxWaitSem adds an event semaphore or a mutex semaphore a MuxWait semaphore list.

Syntax

DosAddMuxWaitSem( hmuxSemaphore, pSemRecord )

Parameters

HMUX hmuxSemaphore (input)
The handle of the MuxWait semaphore to which another semaphore will be added.
PSEMRECORD pSemRecord (input)
The address of a SEMRECORD to be added to the specified MuxWait semaphore.

Returns

APIRET rc

The following values can be returned:

  • 0 NO_ERROR - Operation was successful.
  • 6 ERROR_INVALID_HANDLE - Error, The value in hmuxSemaphore does not point to a valid semaphore, The calling process must first have access to the semaphore in question
  • 8 ERROR_NOT_ENOUGH_MEMORY - Error, The system memory limit has been exhausted
  • 87 ERROR_INVALID_PARAMETER - Error, One or more of the parameters contains an illegal value.
  • 100 ERROR_TOO_MANY_SEMAPHORES - Error, The system limit of 64 semaphores has been exceeded for this MuxWait semaphore.
  • 105 ERROR_SEM_OWNER_DIED - Error, The owner of the MuxWait semaphore specified has terminated.
  • 284 ERROR_DUPLICATE_HANDLE - Error, The semaphore referred to in pSemRecord has already been added to the specified MuxWait semaphore.
  • 292 ERROR_WRONG_TYPE - Error, The semaphore referred to in pSemRecord is of a different

type than those already in the list for hmuxSemaphore.

Gotchas

All processes that have access to a shared MuxWait semaphore must also have access to the event/mutex semaphore that is to be added to the MuxWait list. If a process does not have access to this semaphore then it will unblock and return the error ERROR_INVALID_HANDLE. DosAddMuxWaitSem will NOT return an error in this case. The processes wishing to gain access to the MuxWait semaphore will return errors until proper access has been obtained.

Sample Code

#define INCL_DOSSEMAPHORES
#include <os2.h>

HMUX  hmuxMySemaphore;     /* MySemaphore handle */
SEMRECORD SemRecord;       /* Record containing info about the sem */
                           /* I want to add to MySemaphore's list */

	/* access is gained to the semaphore in question */
	/* either by DosCreateMuxWaitSem ... */
	/* ... or by DosOpenMuxWaitSem */
	/* its handle is placed in hmuxMySemaphore */

	/* SemRecord is filled with appropriate information about */
	/* the semaphore I wish to add to hmuxMySemaphore's list */

	rc = DosAddMuxWaitSem(hmuxMySemaphore, &SemRecord);

	if (rc != 0)
	{
	  /* We got an error to take care of. */
	}

See Also