Set a thread local storage (tls) area
#include <linux/unistd.h>
#include <asm/ldt.h>
int set_thread_area(struct user_desc *u_info);
Note: There is no glibc wrapper for this system call; see NOTES.
set_thread_area() sets an entry in the current thread's thread-local storage (TLS) array. The TLS array entry set by set_thread_area() corresponds to the value of u_info->entry_number passed in by the user. If this value is in bounds, set_thread_area() copies the TLS descriptor pointed to by u_info into the thread's TLS array.
When set_thread_area() is passed an entry_number of -1, it uses a free TLS entry. If set_thread_area() finds a free TLS entry, the value of u_info->entry_number is set upon return to show which entry was changed.
set_thread_area() returns 0 on success, and -1 on failure, with errno set appropriately.
EINVAL
u_info->entry_number is out of bounds.
EFAULT
u_info is an invalid pointer.
ESRCH
A free TLS entry could not be located.
A version of set_thread_area() first appeared in Linux 2.5.29.
set_thread_area() is Linux-specific and should not be used in programs that are intended to be portable.
Glibc does not provide a wrapper for this system call, since it is generally intended only for use by threading libraries. In the unlikely event that you want to call it directly, use syscall(2).
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