pthread_getconcurrency(3THR) returns the value set by a previous call to pthread_setconcurrency(). If the pthread_setconcurrency() function was not previously called, pthread_getconcurrency() returns zero.
#include <pthread.h> int pthread_getconcurrency(void);
pthread_getconcurrency() always returns the concurrency level set by a previous call to pthread_setconcurrency(). If pthread_setconcurrency() has never been called, pthread_getconcurrency() returns zero.