1.\" Copyright (c) 2002,2003 Alexey Zelkin <phantom@FreeBSD.org>
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25.\" $FreeBSD$
26.\"
27.Dd October 12, 2021
28.Dt PTHREAD_ATTR_GET_NP 3
29.Os
30.Sh NAME
31.Nm pthread_attr_get_np
32.Nd get attributes of existent thread
33.Sh LIBRARY
34.Lb libpthread
35.Sh SYNOPSIS
36.In pthread_np.h
37.Ft int
38.Fn pthread_attr_get_np "pthread_t pid" "pthread_attr_t *dst"
39.Sh DESCRIPTION
40The
41.Fn pthread_attr_get_np
42function is used to get existent thread's attributes.
43Most fields of
44.Vt pthread_attr_t
45structure are exact values of attributes provided at thread creation
46time (as parameter to
47.Xr pthread_create 3
48function), except for the stack address.
49.Pp
50Value returned as
51.Fa dst
52is supposed to be used in conjunction with
53.Fn pthread_attr_get*
54functions to retrieve individual values from
55.Vt pthread_attr_t
56structure.
57Parameter
58.Fa dst
59should point to allocated memory area big enough to fit this structure.
60.Pp
61It is HIGHLY RECOMMENDED to use
62.Xr pthread_attr_init 3
63function to allocate attribute storage.
64.Sh IMPLEMENTATION NOTES
65The
66.Fn pthread_attr_get_np
67function will always return a pointer to the thread's real stack address,
68regardless of its value in the original attributes structure.
69.Sh RETURN VALUES
70If successful,
71.Fn pthread_attr_get_np
72function returns 0.
73Otherwise, an error number is returned to indicate the error.
74.Sh EXAMPLES
75.Bd -literal
76size_t
77my_thread_stack_size(pthread_t pid)
78{
79    pthread_attr_t attr;
80    size_t size;
81
82    pthread_attr_init(&attr);
83    pthread_attr_get_np(pid, &attr);
84    pthread_attr_getstacksize(&attr, &size);
85    pthread_attr_destroy(&attr);
86    return(size);
87}
88.Ed
89.Sh ERRORS
90The
91.Fn pthread_attr_get_np
92function will fail if:
93.Bl -tag -width Er
94.It Bq Er EINVAL
95Invalid value for one of given parameters.
96.It Bq Er ESRCH
97No thread could be found corresponding to that specified by the given
98thread ID.
99.El
100.Sh SEE ALSO
101.Xr pthread_attr_destroy 3 ,
102.Xr pthread_attr_getdetachstate 3 ,
103.Xr pthread_attr_getinheritsched 3 ,
104.Xr pthread_attr_getschedparam 3 ,
105.Xr pthread_attr_getschedpolicy 3 ,
106.Xr pthread_attr_getscope 3 ,
107.Xr pthread_attr_getstack 3 ,
108.Xr pthread_attr_getstackaddr 3 ,
109.Xr pthread_attr_getstacksize 3 ,
110.Xr pthread_attr_init 3 ,
111.Xr pthread_np 3
112.Sh AUTHORS
113The
114.Fn pthread_attr_get_np
115function and this manual page were written by
116.An Alexey Zelkin Aq Mt phantom@FreeBSD.org .
117