1.\" Copyright (c) 2003 Alexey Zelkin <phantom@FreeBSD.org> 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 13.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" 25.Dd October 12, 2021 26.Dt PTHREAD_SWITCH_ADD_NP 3 27.Os 28.Sh NAME 29.Nm pthread_switch_add_np , 30.Nm pthread_switch_delete_np 31.Nd thread context switches debugging primitives 32.Sh LIBRARY 33.Lb libpthread 34.Sh SYNOPSIS 35.In pthread_np.h 36.Ft int 37.Fn pthread_switch_add_np "pthread_switch_routine_t routine" 38.Ft int 39.Fn pthread_switch_delete_np "pthread_switch_routine_t routine" 40.Sh DESCRIPTION 41An application is allowed to monitor the thread context switches inside 42the threading library. 43An application can install a routine that gets called every time a thread 44(explicitly created by an application with the 45.Xr pthread_create 3 46function) gets the context switched. 47The routine is passed the thread IDs of the threads that are 48being switched in and out. 49Installation and removal of these hooks may be done using the 50.Fn pthread_switch_add_np 51and 52.Fn pthread_switch_delete_np 53functions respectively. 54.Sh RETURN VALUES 55If successful, 56these functions return 0. 57Otherwise, an error number is returned to indicate the error. 58.Sh ERRORS 59The 60.Fn pthread_switch_add_np 61may fail if: 62.Bl -tag -width Er 63.It Bq Er EINVAL 64.Dv NULL 65pointer was passed in the 66.Fa routine 67argument. 68.El 69.Pp 70The 71.Fn pthread_switch_delete_np 72may fail if: 73.Bl -tag -width Er 74.It Bq Er EINVAL 75The 76.Fa routine 77argument is different from the argument previously passed to the 78.Fn pthread_switch_add_np 79function. 80.El 81.Sh SEE ALSO 82.Xr pthread_create 3 , 83.Xr pthread_np 3 84.Sh AUTHORS 85This manual page was written by 86.An Alexey Zelkin Aq Mt phantom@FreeBSD.org . 87