DosOpenMuxWaitSem
From EDM2
DosOpenMuxWaitSem gains access to a shared MuxWait semaphore.
Syntax
rc = DosOpenMuxWaitSem( pszSemaphoreName,
phmuxSemaphore );
Parameters
- PSZ pszSemaphoreName (input)
- This is a pointer to NULL terminated string containing the name of the shared MuxWait semaphore to access. If this value is NULL then the semaphore to access is specified in phmuxSemaphore.
- PHMUX phmuxSemaphore (input/output)
- For input, this value is a pointer to the MuxWait semaphore handle that should be openned if pszSemaphoreName is NULL. If :pszSemaphoreName is not NULL then this value must be NULL on input. For output, this is a pointer to the MuxWait semaphore handle (HMUX) to the openned semaphore.
Returns
APIRET rc
The following values can be returned:
| 0 | NO_ERROR | Semaphore
opened successfully |
| 6 | ERROR_INVALID_HANDLE | Error, The value in phmuxSemaphore does not point to a valid
semaphore |
| 8 | ERROR_NOT_ENOUGH_MEMORY | Error, The system memory limit has been exceeded |
| 87 | ERROR_INVALID_PARAMETER | Error, One or more parameters is not recognized, See parameters above,
Both pszSemaphoreName and phmuxSemaphore may be NULL |
| 105 | ERROR_SEM_OWNER_DIED | Error, The owner of the semaphore has died without freeing the
semaphore |
| 123 | ERROR_INVALID_NAME | Error, The name pointed to by pszSemaphoreName has been rejected
by the file system |
| 187 | ERROR_SEM_NOT_FOUND | Error, There is no semaphore with the name in
pszSemaphoreName |
| 291 | ERROR_TOO_MANY_OPENS | Error, The usage count for the semaphore in question has exceeded the
system limit of 65535 |
Gotchas
The process that created the MuxWait semaphore does not need to call this. The process wishing to use this function must first have gained access to all semaphores in the muxwait list of the MuxWait semaphore to which access is intended or ERROR_INVALID_HANDLE will be returned.
Sample Code
#define INCL_DOSSEMAPHORES
#include <os2.h>
#include <string.h>
int main(){
UCHAR SemName[15];
PHMUX phmuxMySemaphore = NULL; /* pointer to semaphore handle */
APIRET rc;
/* a shared MuxWait semaphore is successfully created in another process */
/* its name happens to be \SEM32\MySem */
strcpy(SemName,"\\SEM32\\MySem");
rc = DosOpenMuxWaitSem(SemName, phmuxMySemaphore);
if (rc != 0) {
/* We got an error to take care of. */
}
}
