pthread_rwlock_setname_np()--Set Name in Read/Write Lock

 #include <pthread.h>
 int pthread_rwlock_setname_np(pthread_rwlock_t *rwlock,
                               const char *name);
  Service Program Name: QP0WPTHR

  Default Public Authority: *USE

  Threadsafe: Yes

  Signal Safe: Yes

The pthread_rwlock_setname_np() function sets the name of the read/write lock specified by rwlock. The buffer specified by name must contain a null terminated string of 15 characters or less in length (not including the NULL). If the length of name is greater than 15 characters, the excess characters are ignored. If name is null, the read/write lock name is reset to the default.

By default, each pthread_rwlock_t does not have a name associated with it.

Note: This function is not portable.


(Input) The address of the read/write lock object.
(Input) Address of a null terminated character buffer containing the name

Authorities and Locks


Return Value

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

Error Conditions

If pthread_rwlock_setname_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.

Usage Notes

Related Information


The following example will set the read/write lock 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_rwlock_t    rwlock;

int main(int argc, char **argv)
  int                   rc=0;
  pthread_rwlockattr_t    rwa;
  char readWriteLockName[16];

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

  printf("Create a default read/write lock attribute\n");
  rc = pthread_rwlockattr_init(&rwa);
  checkResults("pthread_rwlockattr_init\n", rc);

  printf("Create the read/write lock using a read/write lock attributes object\n");
  rc = pthread_rwlock_init(&rwlock, &rwa);
  checkResults("pthread_rwlock_init\n", rc);

  memset(readWriteLockName, 0, sizeof(readWriteLockName));
  strcpy(readWriteLockName,"READWRITE LOCK1");
  printf("Set the name of the read/write lock\n");
  rc = pthread_rwlock_setname_np(&rwlock, readWriteLockName);
  checkResults("pthread_rwlock_setname_np\n", rc);

  memset(readWriteLockName, 0, sizeof(readWriteLockName));
  printf("Get the name of the read/write lock\n");
  rc = pthread_rwlock_getname_np(&rwlock, readWriteLockName);
  checkResults("pthread_rwlock_getname_np\n", rc);
  printf("The read/write lock name is: %.15s\n", readWriteLockName);

  printf("Destroy the read/write lock\n");

  printf("Main completed\n");
  return 0;
Example Output:
Enter Testcase - QP0WTEST/TPCRT0
Create a default read/write lock attribute
Create the read/write lock using a read/write lock attributes object
Set the name of the read/write lock
Get the name of the read/write lock
The read/write lock name is: READWRITE LOCK1
Destroy the read/write lock
Main completed

API introduced: IBM® i 7.1

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