1.\" Copyright (c) 2003 Alexey Zelkin <phantom@FreeBSD.org>
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25.\" $FreeBSD: src/share/man/man3/pthread_switch_add_np.3,v 1.5 2007/10/22 10:08:01 ru Exp $
26.\" $DragonFly: src/lib/libc_r/man/pthread_switch_add_np.3,v 1.3 2005/08/01 01:49:16 swildner Exp $
27.\"
28.Dd July 10, 2009
29.Dt PTHREAD_SWITCH_ADD_NP 3
30.Os
31.Sh NAME
32.Nm pthread_switch_add_np ,
33.Nm pthread_switch_delete_np
34.Nd thread context switches debugging primitives
35.Sh LIBRARY
36.Lb libpthread
37.Sh SYNOPSIS
38.In pthread.h
39.In pthread_np.h
40.Ft int
41.Fn pthread_switch_add_np "pthread_switch_routine_t routine"
42.Ft int
43.Fn pthread_switch_delete_np "pthread_switch_routine_t routine"
44.Sh DESCRIPTION
45An application is allowed to monitor the thread context switches inside
46the threading library.
47An application can install a routine that gets called every time a thread
48(explicitly created by an application with the
49.Xr pthread_create 3
50function) gets the context switched.
51The routine is passed the thread IDs of the threads that are
52being switched in and out.
53Installation and removal of these hooks may be done using the
54.Fn pthread_switch_add_np
55and
56.Fn pthread_switch_delete_np
57functions respectively.
58.Sh RETURN VALUES
59If successful,
60these functions return 0.
61Otherwise, an error number is returned to indicate the error.
62.Sh ERRORS
63The
64.Fn pthread_switch_add_np
65may fail if:
66.Bl -tag -width Er
67.It Bq Er EINVAL
68.Dv NULL
69pointer was passed in the
70.Fa routine
71argument.
72.El
73.Pp
74The
75.Fn pthread_switch_delete_np
76may fail if:
77.Bl -tag -width Er
78.It Bq Er EINVAL
79The
80.Fa routine
81argument is different from the argument previously passed to the
82.Fn pthread_switch_add_np
83function.
84.El
85.Sh SEE ALSO
86.Xr pthread_create 3
87.Sh AUTHORS
88This manual page was written by
89.An Alexey Zelkin Aq phantom@FreeBSD.org .
90