1.\" Copyright (c) 2002,2003 Alexey Zelkin <phantom@FreeBSD.org>
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6.\" <olce@FreeBSD.org> at Kumacom SARL under sponsorship from the
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30.Dd January 5, 2024
31.Dt PTHREAD_ATTR_GET_NP 3
32.Os
33.Sh NAME
34.Nm pthread_attr_get_np
35.Nd get attributes of an existing thread
36.Sh LIBRARY
37.Lb libpthread
38.Sh SYNOPSIS
39.In pthread_np.h
40.Ft int
41.Fn pthread_attr_get_np "pthread_t pid" "pthread_attr_t *dst"
42.Sh DESCRIPTION
43The
44.Fn pthread_attr_get_np
45function is used to retrieve the attributes of the specified thread into an
46existing
47.Vt pthread_attr_t
48structure.
49The attributes' values are the current ones for the target thread, except for
50the stack top address if not properly aligned for the architecture, since in
51this case its value has been adjusted internally before use.
52.Pp
53Argument
54.Fa dst
55must be a pointer to a valid attributes object
56.Po
57it was initialized at some point by
58.Xr pthread_attr_init 3
59and was not destroyed since then
60.Pc .
61After a successful call to
62.Fn pthread_attr_get_np ,
63the individual attributes' values can be retrieved as usual via the
64corresponding accessor functions as documented in
65.Xr pthread_attr 3 .
66After a failed call to
67.Fn pthread_attr_get_np ,
68the object pointed to by
69.Fa dst
70is left unmodified, and can continue to be used as if the failed call never
71happened.
72.Sh RETURN VALUES
73If successful,
74.Fn pthread_attr_get_np
75function returns 0.
76Otherwise, an error number is returned to indicate the error.
77.Sh EXAMPLES
78This function retrieves the stack size of the thread specified by the
79.Fa pid
80argument:
81.Bd -literal
82size_t
83my_thread_stack_size(pthread_t tid)
84{
85	pthread_attr_t attr;
86	size_t size;
87
88	pthread_attr_init(&attr);
89	pthread_attr_get_np(tid, &attr);
90	pthread_attr_getstacksize(&attr, &size);
91	pthread_attr_destroy(&attr);
92	return (size);
93}
94.Ed
95.Sh ERRORS
96The
97.Fn pthread_attr_get_np
98function will fail if:
99.Bl -tag -width Er
100.It Bq Er EINVAL
101One of the arguments has an invalid value.
102.It Bq Er ESRCH
103No thread could be found corresponding to that specified by the given
104thread ID.
105.It Bq Er ENOMEM
106There was not enough memory to allocate additional storage needed by the attributes
107object's implementation.
108.El
109.Sh SEE ALSO
110.Xr pthread_attr 3 ,
111.Xr pthread_attr_destroy 3 ,
112.Xr pthread_attr_getdetachstate 3 ,
113.Xr pthread_attr_getinheritsched 3 ,
114.Xr pthread_attr_getschedparam 3 ,
115.Xr pthread_attr_getschedpolicy 3 ,
116.Xr pthread_attr_getscope 3 ,
117.Xr pthread_attr_getstack 3 ,
118.Xr pthread_attr_getstackaddr 3 ,
119.Xr pthread_attr_getstacksize 3 ,
120.Xr pthread_attr_init 3 ,
121.Xr pthread_np 3
122.Sh AUTHORS
123The
124.Fn pthread_attr_get_np
125function and this manual page were written by
126.An Alexey Zelkin Aq Mt phantom@FreeBSD.org ,
127and the latter was revised by
128.An Olivier Certner Aq Mt olce@FreeBSD.org .
129