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.Dd May 5, 2020 .Dt THR_SELF 2 .Os .Sh NAME .Nm thr_self .Nd return thread identifier for the calling thread .Sh LIBRARY .Lb libc .Sh SYNOPSIS n sys/thr.h .Ft int .Fn thr_self "long *id" .Sh DESCRIPTION The .Fn thr_self system call stores the system-wide thread identifier for the current kernel-scheduled thread in the variable pointed by the argument .Va id .
p The thread identifier is an integer in the range from .Dv PID_MAX + 2 (100001) to .Dv INT_MAX . The thread identifier is guaranteed to be unique at any given time, for each running thread in the system. After the thread exits, the identifier may be reused. .Sh RETURN VALUES If successful, .Fn thr_self will return zero, otherwise -1 is returned, and .Va errno is set to indicate the error. .Sh ERRORS The .Fn thr_self operation may return the following errors: l -tag -width Er t Bq Er EFAULT The memory pointed to by the .Fa id argument is not valid. .El .Sh SEE ALSO .Xr _umtx_op 2 , .Xr thr_exit 2 , .Xr thr_kill 2 , .Xr thr_kill2 2 , .Xr thr_new 2 , .Xr thr_set_name 2 , .Xr pthread_getthreadid_np 3 , .Xr pthread_self 3 .Sh STANDARDS The .Fn thr_self system call is non-standard and is used by .Lb libthr to implement .St -p1003.1-2001 .Xr pthread 3 functionality. .Sh HISTORY The .Fn thr_self system call first appeared in .Fx 5.2 .