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Syntax #include <pthread.h> pthread_t pthread_self(void); Threadsafe: Yes Signal Safe: Yes |
The pthread_self() function returns the Pthread handle of the calling thread. The pthread_self() function does NOT return the integral thread of the calling thread. You must use pthread_getthreadid_np() to return an integral identifier for the thread.
If your code requires the unique integer identifier for the calling thread often, or in a loop, the pthread_getthreadid_np() function can provide significant performance improvements over the combination of pthread_self(), and pthread_getunique_np() calls that provide equivalent behavior.
For example:
pthread_id_np_t tid; tid = pthread_getthreadid_np();is significantly faster than these calls, but provides the same behavior.
pthread_id_np_t tid; pthread_t self; self = pthread_self(); pthread_getunique_np(&self, &tid);As always, if you are calling any function too often, performance improvements can be gained by storing the results in a variable and or passing to other functions which require the results.
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#include <pthread.h>
#include <pthread.h>
#include <stdio.h>
#include "check.h"
pthread_t theThread;
void *threadfunc(void *parm)
{
printf("Inside secondary thread\n");
theThread = pthread_self();
return NULL;
}
int main(int argc, char **argv)
{
pthread_t thread;
int rc=0;
printf("Entering testcase\n");
printf("Create thread using default attributes\n");
rc = pthread_create(&thread, NULL, threadfunc, NULL);
checkResults("pthread_create()\n", rc);
/* sleep() isn't a very robust way to wait for the thread */
sleep(5);
printf("Check if the thread got its thread handle\n");
if (!pthread_equal(thread, theThread)) {
printf("Unexpected results on pthread_equal()!\n");
exit(1);
}
printf("pthread_self() returned the thread handle\n");
printf("Main completed\n");
return 0;
}
Output
Entering testcase Create thread using default attributes Inside secondary thread Check if the thread got its thread handle pthread_self() returned the thread handle Main completed