NAME

pthread_attr_get_np, pthread_getattr_np — get attributes of existing thread

LIBRARY

POSIX Threads Library (libpthread, -lpthread)

SYNOPSIS

#include <pthread.h>

int
pthread_attr_get_np(pthread_t thread, pthread_attr_t *attr);

int
pthread_getattr_np(pthread_t thread, pthread_attr_t *attr);

DESCRIPTION

The pthread_attr_get_np() and pthread_getattr_np() functions can be used to retrieve attributes of a running thread. The result is stored to attr.

For pthread_attr_get_np() attr should be initialized prior to the call by using pthread_attr_init(3). pthread_getattr_np() does this automatically.

For both functions attr should be freed when it is not in use anymore with pthread_attr_destroy(3).

Most fields of attr are the same ones provided during thread creation time as a parameter to pthread_create(3). The exceptions include:

The detach state -- a joinable thread may have detached itself after the creation.
The guard size, which may vary if the application has allocated its own thread stack.
The stack address and size; pthread_attr_get_np() will always return the thread's real stack address and size, regardless of the values in the original attributes structure.

The returned pthread_attr_t structure is supposed to be used in conjunction with the pthread_attr_get*() functions to retrieve individual values from the structure. When the returned attr is no longer needed, it should be destroyed by using pthread_attr_destroy(3).

RETURN VALUES

Upon successful completion, pthread_attr_get_np() and pthread_getattr_np() return 0. Otherwise an error number is returned to indicate the error.

COMPATIBILITY

The pthread_attr_get_np() and pthread_getattr_np() functions are non-standard extensions.

ERRORS

The pthread_attr_get_np() and pthread_getattr_np() functions will fail if:

[ENOMEM]: Insufficient memory.
[ESRCH]: Non-existent thread.