xref: /freebsd/contrib/libpcap/thread-local.h (revision b64c5a0ace59af62eff52bfe110a521dc73c937b)
1 /*
2  * Copyright (c) 1994, 1995, 1996
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the Computer Systems
16  *	Engineering Group at Lawrence Berkeley Laboratory.
17  * 4. Neither the name of the University nor of the Laboratory may be used
18  *    to endorse or promote products derived from this software without
19  *    specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef thread_local_h
35 #define	thread_local_h
36 
37 /*
38  * This defines thread_local to specify thread-local storage, if it
39  * is not already defined.
40  *
41  * C11, if __STDC_NO_THREADS__ is not defined to be 1, defines
42  * _Thread_local to indicate thread-local storage.  (You can also
43  * include <threads.h> to so define it, but we don't use any of
44  * the other stuff there.)
45  *
46  * Otherwise, we define it ourselves, based on the compiler.
47  *
48  * This is taken from https://stackoverflow.com/a/18298965/16139739.
49  */
50 #ifndef thread_local
51   #if __STDC_VERSION__ >= 201112 && !defined __STDC_NO_THREADS__
52     #define thread_local _Thread_local
53   #elif defined __TINYC__
54     #define thread_local
55     #warning "Some libpcap calls will not be thread-safe."
56   #elif defined _WIN32 && ( \
57          defined _MSC_VER || \
58          defined __ICL || \
59          defined __DMC__ || \
60          defined __BORLANDC__ )
61     #define thread_local __declspec(thread)
62   /* note that ICC (linux) and Clang are covered by __GNUC__ */
63   #elif defined __GNUC__ || \
64          defined __SUNPRO_C || \
65          defined __xlC__
66     #define thread_local __thread
67   #else
68     #error "Cannot define thread_local"
69   #endif
70 #endif
71 
72 #endif
73