PTHREAD_ATTR_GET_NP(3)                        FreeBSD Library Functions Manual

NAME
     pthread_attr_get_np - get attributes of existent thread

LIBRARY
     POSIX Threads Library (libpthread, -lpthread)

SYNOPSIS
     #include <pthread_np.h>

     int
     pthread_attr_get_np(pthread_t pid, pthread_attr_t *dst);

DESCRIPTION
     The pthread_attr_get_np() function is used to get existent thread's
     attributes.  Most fields of pthread_attr_t structure are exact values of
     attributes provided at thread creation time (as parameter to
     pthread_create(3) function), except for the stack address.

     Value returned as dst is supposed to be used in conjunction with
     pthread_attr_get*() functions to retrieve individual values from
     pthread_attr_t structure.  Parameter dst should point to allocated memory
     area big enough to fit this structure.

     It is HIGHLY RECOMMENDED to use pthread_attr_init(3) function to allocate
     attribute storage.

IMPLEMENTATION NOTES
     The pthread_attr_get_np() function will always return a pointer to the
     thread's real stack address, regardless of its value in the original
     attributes structure.

RETURN VALUES
     If successful, pthread_attr_get_np() function returns 0.  Otherwise, an
     error number is returned to indicate the error.

EXAMPLES
     size_t
     my_thread_stack_size(pthread_t pid)
     {
         pthread_attr_t attr;
         size_t size;

         pthread_attr_init(&attr);
         pthread_attr_get_np(pid, &attr);
         pthread_attr_getstacksize(&attr, &size);
         pthread_attr_destroy(&attr);
         return(size);
     }

ERRORS
     The pthread_attr_get_np() function will fail if:

     [EINVAL]           Invalid value for one of given parameters.

     [ESRCH]            No thread could be found corresponding to that
                        specified by the given thread ID.

SEE ALSO
     pthread_attr_destroy(3), pthread_attr_getdetachstate(3),
     pthread_attr_getinheritsched(3), pthread_attr_getschedparam(3),
     pthread_attr_getschedpolicy(3), pthread_attr_getscope(3),
     pthread_attr_getstack(3), pthread_attr_getstackaddr(3),
     pthread_attr_getstacksize(3), pthread_attr_init(3), pthread_np(3)

AUTHORS
     The pthread_attr_get_np() function and this manual page were written by
     Alexey Zelkin <phantom@FreeBSD.org>.

FreeBSD 13.1-RELEASE-p6        October 12, 2021        FreeBSD 13.1-RELEASE-p6