pthread_mutex_getname_np()--Get Name from Mutex

 #include <pthread.h>
 int pthread_mutex_getname_np(pthread_mutex_t *mutex,  
                              char *name);
  Service Program Name: QP0WPTHR

  Default Public Authority: *USE

  Threadsafe: Yes

  Signal Safe: Yes

The pthread_mutex_getname_np() function retrieves the name of the specified mutex. The buffer specified by name must be at least 16 characters in length. The returned mutex name will be null terminated in the output buffer.

By default, each pthread_mutex_t has the name "QP0WMTX UNNAMED" associated with it. The name attribute is used by various IBM i system utilities to aid in debug and service. One example is the WRKJOB command, which has a `work with mutexes' menu choice to show which mutexes are currently locked and which mutexes are being waited for.

You should give unique names to all mutexes created to aid in debugging deadlock or performance problems. Use the CL command WRKJOB, option 20, to help debug mutex deadlocks.

Note: This function is not portable.


(Input) The address of the mutex object
(Output) Address of 16 byte buffer to receive the name

Authorities and Locks


Return Value

pthread_mutex_getname_np() was successful.
pthread_mutex_getname_np() was not successful. value is set to indicate the error condition.

Error Conditions

If pthread_mutex_getname_np() was not successful, the error condition returned usually indicates one of the following errors. Under some conditions, the value returned could indicate an error other than those listed here.

Related Information


The following example will get the mutex name.

Note: By using the code examples, you agree to the terms of the Code license and disclaimer information.

#include <pthread.h>
#include <stdio.h>
#include <errno.h>
#include "check.h"

pthread_mutex_t    mutex;

int main(int argc, char **argv)
  int                   rc=0;
  pthread_mutexattr_t   mta;
  char mutexName[16];

  printf("Enter Testcase - %s\n", argv[0]);

  printf("Create a default mutex attribute\n");
  rc = pthread_mutexattr_init(&mta);
  checkResults("pthread_mutexattr_init\n", rc);

  printf("Create the mutex using a mutex attributes object\n");
  rc = pthread_mutex_init(&mutex2, &mta);
  checkResults("pthread_mutex_init(mta)\n", rc);

  memset(mutexName, 0, sizeof(mutexName));
  printf("Get the default name of the mutex\n");
  rc = pthread_mutex_getname_np(&mutex, mutexName);
  checkResults("pthread_mutex_getname_np\n", rc);
  printf("The default mutex name is: %.15s\n", mutexName);

  printf("Destroy the mutex\n");

  printf("Main completed\n");
  return 0;

Example Output:
Enter Testcase - QP0WTEST/TPCRT0
Create a default mutex attribute
Create the mutex using a mutex attributes object
Get the default name of the mutex
The default mutex name is: QP0WMTX UNNAMED
Destroy the mutex
Main completed

API introduced: IBM® i 7.1

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