Tor  0.4.6.0-alpha-dev
tokpaste.h
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1 /* Copyright (c) 2001 Matej Pfajfar.
2  * Copyright (c) 2001-2004, Roger Dingledine.
3  * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
4  * Copyright (c) 2007-2020, The Tor Project, Inc. */
5 /* See LICENSE for licensing information */
6 
7 /**
8  * @file tokpaste.h
9  * @brief Token-pasting macros.
10  **/
11 
12 #ifndef TOR_LIB_CC_TOKPASTE_H
13 #define TOR_LIB_CC_TOKPASTE_H
14 
15 /**
16  * Concatenate `a` and `b` in a way that allows their result itself to be
17  * expanded by the preprocessor.
18  *
19  * Ordinarily you could just say `a ## b` in a macro definition. But doing so
20  * results in a symbol which the preprocessor will not then expand. If you
21  * wanted to use `a ## b` to create the name of a macro and have the
22  * preprocessor expand _that_ macro, you need to have another level of
23  * indirection, as this macro provides.
24  **/
25 #define PASTE(a,b) PASTE__(a,b)
26 
27 /** Helper for PASTE(). */
28 #define PASTE__(a,b) a ## b
29 
30 #endif /* !defined(TOR_LIB_CC_TOKPASTE_H) */