.\" Copyright (c) 2002,2003 Alexey Zelkin <phantom@FreeBSD.org>
.\" All rights reserved.
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.\" $FreeBSD: head/share/man/man3/pthread_attr_get_np.3 301076 2016-05-31 21:09:42Z jilles $
.\"
.Dd January 31, 2003
.Dt PTHREAD_ATTR_GET_NP 3
.Os
.Sh NAME
.Nm pthread_attr_get_np
.Nd get attributes of existent thread
.Sh LIBRARY
.Lb libpthread
.Sh SYNOPSIS
.In pthread_np.h
.Ft int
.Fn pthread_attr_get_np "pthread_t pid" "pthread_attr_t *dst"
.Sh DESCRIPTION
The
.Fn pthread_attr_get_np
function is used to get existent thread's attributes.
Most fields of
.Vt pthread_attr_t
structure are exact values of attributes provided at thread creation
time (as parameter to
.Xr pthread_create 3
function), except for the stack address.
.Pp
Value returned as
.Fa dst
is supposed to be used in conjunction with
.Fn pthread_attr_get*
functions to retrieve individual values from
.Vt pthread_attr_t
structure.
Parameter
.Fa dst
should point to allocated memory area big enough to fit this structure.
.Pp
It is HIGHLY RECOMMENDED to use
.Xr pthread_attr_init 3
function to allocate attribute storage.
.Sh IMPLEMENTATION NOTES
The
.Fn 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.
.Sh RETURN VALUES
If successful,
.Fn pthread_attr_get_np
function returns 0.
Otherwise, an error number is returned to indicate the error.
.Sh EXAMPLES
.Bd -literal
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);
}
.Ed
.Sh ERRORS
The
.Fn pthread_attr_get_np
function will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
Invalid value for one of given parameters.
.It Bq Er ESRCH
No thread could be found corresponding to that specified by the given
thread ID.
.El
.Sh SEE ALSO
.Xr pthread_attr_destroy 3 ,
.Xr pthread_attr_getdetachstate 3 ,
.Xr pthread_attr_getinheritsched 3 ,
.Xr pthread_attr_getschedparam 3 ,
.Xr pthread_attr_getschedpolicy 3 ,
.Xr pthread_attr_getscope 3 ,
.Xr pthread_attr_getstack 3 ,
.Xr pthread_attr_getstackaddr 3 ,
.Xr pthread_attr_getstacksize 3 ,
.Xr pthread_attr_init 3
.Sh AUTHORS
The
.Fn pthread_attr_get_np
function and this manual page were written by
.An Alexey Zelkin Aq Mt phantom@FreeBSD.org .