pthread_attr_getweight_np() — Get weight of thread attribute object

Standards

Standards / Extensions C or C++ Dependencies
z/OS® UNIX both
POSIX(ON)

Format

#define _OPEN_THREADS
#define _OPEN_SYS
#include <pthread.h>

int pthread_attr_getweight_np(pthread_attr_t *attr);

General description

Obtains the current weight of the thread setting of the thread attributes object, attr. The symbols for weight are defined in the pthread.h include file. The following weights are supported:
__MEDIUM_WEIGHT
The executing task can be reused when the thread exits.
__HEAVY_WEIGHT
When this exits, the associated MVS™ task can no longer request threads to process.

You can use a thread attribute object to manage the characteristics of threads in your application. It defines the set of values to be used for the thread during its creation. By establishing a thread attribute object, you can create many threads with the same set of characteristics, without defining those characteristics for each and every thread. You can define more than one thread attribute object.

Returned value

If successful, pthread_attr_getweight_np() returns the value of the weight of the thread attribute.

If unsuccessful, pthread_attr_getweight_np() returns -1.

There are no documented errno values. Use perror() or strerror() to determine the cause of the error.

Example

CELEBP09 
/* CELEBP08 */
#define _OPEN_THREADS
#define _OPEN_SYS           /* Needed to identify __HEAVY_WEIGHT AND
                             __MEDIUM WEIGHT  */
#include <stdio.h>
#include <pthread.h>

int main()
{
   pthread_attr_t attr;
   char           weight[12];

   if (pthread_attr_init(&attr) == -1) {
      perror("error in pthread_attr_init");
      exit(1);
   }

   switch(pthread_attr_getweight_np(&attr)) {
      default:
         perror("error in pthread_attr_getweight_np()");
         exit(2);
      case __HEAVY_WEIGHT:
         strcpy(weight, "heavy");
         break;
      case __MEDIUM_WEIGHT:
         strcpy(weight, "medium");
   }
   printf("The thread weight is %s.\n", weight);

   if (pthread_attr_destroy(&attr) == -1) {
      perror("error in pthread_attr_destroy");
      exit(2);
   }
   exit(0);
}
Output: 
The thread weight is heavy.

Related information