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.Dd May 5, 2020
.Dt THR_SET_NAME 2
.Os
.Sh NAME
.Nm thr_set_name
.Nd set user-visible thread name
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/thr.h
.Ft int
.Fn thr_set_name "long id" "const char *name"
.Sh DESCRIPTION
The
.Fn thr_set_name
system call sets the user-visible name for the thread with the identifier
.Va id
in the current process to the NUL-terminated string
.Va name .
The name will be silently truncated to fit into a buffer of
.Dv MAXCOMLEN + 1
bytes.
The thread name can be seen in the output of the
.Xr ps 1
and
.Xr top 1
commands, in the kernel debuggers and kernel tracing facility outputs,
and in userland debuggers and program core files, as notes.
.Sh RETURN VALUES
If successful,
.Fn thr_set_name
returns zero; otherwise, \-1 is returned, and
.Va errno
is set to indicate the error.
.Sh ERRORS
The
.Fn thr_set_name
system call may return the following errors:
.Bl -tag -width Er
.It Bq Er EFAULT
The memory pointed to by the
.Fa name
argument is not valid.
.It Bq Er ESRCH
The thread with the identifier
.Fa id
does not exist in the current process.
.El
.Sh SEE ALSO
.Xr ps 1 ,
.Xr _umtx_op 2 ,
.Xr thr_exit 2 ,
.Xr thr_kill 2 ,
.Xr thr_kill2 2 ,
.Xr thr_new 2 ,
.Xr thr_self 2 ,
.Xr pthread_set_name_np 3 ,
.Xr ddb 4 ,
.Xr ktr 9
.Sh STANDARDS
The
.Fn thr_set_name
system call is non-standard and is used by the
.Lb libthr .
.Sh HISTORY
The
.Fn thr_set_name
system call first appeared in
.Fx 5.2 .