From 74b60c5712f2a84904b95d008953c140a9bd5dd2 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 12:49:50 +0200 Subject: Adding upstream version 2.9.4. Signed-off-by: Daniel Baumann --- gl/lib/windows-once.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 gl/lib/windows-once.c (limited to 'gl/lib/windows-once.c') diff --git a/gl/lib/windows-once.c b/gl/lib/windows-once.c new file mode 100644 index 0000000..c431bd6 --- /dev/null +++ b/gl/lib/windows-once.c @@ -0,0 +1,62 @@ +/* Once-only control (native Windows implementation). + Copyright (C) 2005-2020 Free Software Foundation, Inc. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3, or (at your option) + any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, see . */ + +/* Written by Bruno Haible , 2005. + Based on GCC's gthr-win32.h. */ + +#include + +/* Specification. */ +#include "windows-once.h" + +#include + +void +glwthread_once (glwthread_once_t *once_control, void (*initfunction) (void)) +{ + if (once_control->inited <= 0) + { + if (InterlockedIncrement (&once_control->started) == 0) + { + /* This thread is the first one to come to this once_control. */ + InitializeCriticalSection (&once_control->lock); + EnterCriticalSection (&once_control->lock); + once_control->inited = 0; + initfunction (); + once_control->inited = 1; + LeaveCriticalSection (&once_control->lock); + } + else + { + /* Don't let once_control->started grow and wrap around. */ + InterlockedDecrement (&once_control->started); + /* Some other thread has already started the initialization. + Yield the CPU while waiting for the other thread to finish + initializing and taking the lock. */ + while (once_control->inited < 0) + Sleep (0); + if (once_control->inited <= 0) + { + /* Take the lock. This blocks until the other thread has + finished calling the initfunction. */ + EnterCriticalSection (&once_control->lock); + LeaveCriticalSection (&once_control->lock); + if (!(once_control->inited > 0)) + abort (); + } + } + } +} -- cgit v1.2.3