[wxWidgets.git] / include / wx / cpp.h

/*
 *  Name:        wx/cpp.h
 *  Purpose:     Various preprocessor helpers
 *  Author:      Vadim Zeitlin
 *  Created:     2006-09-30
 *  RCS-ID:      $Id$
 *  Copyright:   (c) 2006 Vadim Zeitlin <vadim@wxwindows.org>
 *  Licence:     wxWindows licence
 */

/* THIS IS A C FILE, DON'T USE C++ FEATURES (IN PARTICULAR COMMENTS) IN IT */

#ifndef _WX_CPP_H_
#define _WX_CPP_H_

/* wxCONCAT works like preprocessor ## operator but also works with macros */
#define wxCONCAT_HELPER(text, line) text ## line

#define wxCONCAT(x1, x2) \
    wxCONCAT_HELPER(x1, x2)
#define wxCONCAT3(x1, x2, x3) \
    wxCONCAT(wxCONCAT(x1, x2), x3)
#define wxCONCAT4(x1, x2, x3, x4) \
    wxCONCAT(wxCONCAT3(x1, x2, x3), x4)
#define wxCONCAT5(x1, x2, x3, x4, x5) \
    wxCONCAT(wxCONCAT4(x1, x2, x3, x4), x5)
#define wxCONCAT6(x1, x2, x3, x4, x5, x6) \
    wxCONCAT(wxCONCAT5(x1, x2, x3, x4, x5), x6)
#define wxCONCAT7(x1, x2, x3, x4, x5, x6, x7) \
    wxCONCAT(wxCONCAT6(x1, x2, x3, x4, x5, x6), x7)
#define wxCONCAT8(x1, x2, x3, x4, x5, x6, x7, x8) \
    wxCONCAT(wxCONCAT7(x1, x2, x3, x4, x5, x6, x7), x8)
#define wxCONCAT9(x1, x2, x3, x4, x5, x6, x7, x8, x9) \
    wxCONCAT(wxCONCAT8(x1, x2, x3, x4, x5, x6, x7, x8), x9)

/* wxSTRINGIZE works as the preprocessor # operator but also works with macros */
#define wxSTRINGIZE_HELPER(x)       #x
#define wxSTRINGIZE(x)              wxSTRINGIZE_HELPER(x)

/* a Unicode-friendly version of wxSTRINGIZE_T */
#define wxSTRINGIZE_T(x)            wxAPPLY_T(wxSTRINGIZE(x))

/*
    Special workarounds for compilers with broken "##" operator. For all the
    other ones we can just use it directly.
 */
#ifdef wxCOMPILER_BROKEN_CONCAT_OPER
    #define wxPREPEND_L(x)      L ## x
    #define wxAPPEND_i64(x)     x ## i64
    #define wxAPPEND_ui64(x)    x ## ui64
#endif /* wxCOMPILER_BROKEN_CONCAT_OPER */

/*
   Helper macros for wxMAKE_UNIQUE_NAME: normally this works by appending the
   current line number to the given identifier to reduce the probability of the
   conflict (it may still happen if this is used in the headers, hence you
   should avoid doing it or provide unique prefixes then) but we have to do it
   differently for VC++
  */
#if defined(__VISUALC__) && (__VISUALC__ >= 1300)
    /*
       __LINE__ handling is completely broken in VC++ when using "Edit and
       Continue" (/ZI option) and results in preprocessor errors if we use it
       inside the macros. Luckily VC7 has another standard macro which can be
       used like this and is even better than __LINE__ because it is globally
       unique.
     */
#   define wxCONCAT_LINE(text)         wxCONCAT(text, __COUNTER__)
#else /* normal compilers */
#   define wxCONCAT_LINE(text)         wxCONCAT(text, __LINE__)
#endif

/* Create a "unique" name with the given prefix */
#define wxMAKE_UNIQUE_NAME(text)    wxCONCAT_LINE(text)

/*
   This macro can be passed as argument to another macro when you don't have
   anything to pass in fact.
 */
#define wxEMPTY_PARAMETER_VALUE /* Fake macro parameter value */

/*
    Helpers for defining macros that expand into a single statement.

    The standatd solution is to use "do { ... } while (0)" statement but MSVC
    generates a C4127 "condition expression is constant" warning for it so we
    use something which is just complicated enough to not be recognized as a
    constant but still simple enough to be optimized away.

    Another solution would be to use __pragma() to temporarily disable C4127.

    Notice that wxASSERT_ARG_TYPE in wx/strvargarg.h relies on these macros
    creating some kind of a loop because it uses "break".
 */
#ifdef __WATCOMC__
    #define wxFOR_ONCE(name) for(int name=0; name<1; name++)
    #define wxSTATEMENT_MACRO_BEGIN wxFOR_ONCE(wxMAKE_UNIQUE_NAME(wxmacro)) {
    #define wxSTATEMENT_MACRO_END }
#else
    #define wxSTATEMENT_MACRO_BEGIN  do {
    #define wxSTATEMENT_MACRO_END } while ( (void)0, 0 )
#endif

/*
    Define __WXFUNCTION__ which is like standard __FUNCTION__ but defined as
    NULL for the compilers which don't support the latter.
 */
#ifndef __WXFUNCTION__
    /* TODO: add more compilers supporting __FUNCTION__ */
    #if defined(__DMC__)
        /*
           __FUNCTION__ happens to be not defined within class members
           http://www.digitalmars.com/drn-bin/wwwnews?c%2B%2B.beta/485
        */
        #define __WXFUNCTION__ (NULL)
    #elif defined(__GNUC__) || \
          (defined(_MSC_VER) && _MSC_VER >= 1300) || \
          defined(__FUNCTION__)
        #define __WXFUNCTION__ __FUNCTION__
    #else
        /* still define __WXFUNCTION__ to avoid #ifdefs elsewhere */
        #define __WXFUNCTION__ (NULL)
    #endif
#endif /* __WXFUNCTION__ already defined */


#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || \
    (defined(__cplusplus) && __cplusplus >= 201103L)
    #define wxHAS_VARIADIC_MACROS
#elif defined(__GNUC__) && __GNUC__ >= 3
    #define wxHAS_VARIADIC_MACROS
#elif defined(_MSC_VER) && _MSC_VER >= 1400
    #define wxHAS_VARIADIC_MACROS
#endif

#ifdef wxHAS_VARIADIC_MACROS
/*
   wxCALL_FOR_EACH(what, ...) calls the macro from its first argument, what(pos, x),
   for every remaining argument 'x', with 'pos' being its 1-based index in
   *reverse* order (with the last argument being numbered 1).

   For example, wxCALL_FOR_EACH(test, a, b, c) expands into this:

       test(3, a) \
       test(2, b) \
       test(1, c)

   Up to eight arguments are supported.

   (With thanks to https://groups.google.com/d/topic/comp.std.c/d-6Mj5Lko_s/discussion
   and http://stackoverflow.com/questions/1872220/is-it-possible-to-iterate-over-arguments-in-variadic-macros)
*/
#define wxCALL_FOR_EACH_NARG(...)   wxCALL_FOR_EACH_NARG_((__VA_ARGS__, wxCALL_FOR_EACH_RSEQ_N()))
#define wxCALL_FOR_EACH_NARG_(args) wxCALL_FOR_EACH_ARG_N args
#define wxCALL_FOR_EACH_ARG_N(_1, _2, _3, _4, _5, _6, _7, _8, N, ...) N
#define wxCALL_FOR_EACH_RSEQ_N() 8, 7, 6, 5, 4, 3, 2, 1, 0

#define wxCALL_FOR_EACH_1(what, x)        what(1, x)
#define wxCALL_FOR_EACH_2(what, x, ...)   what(2, x)  wxCALL_FOR_EACH_1(what,  __VA_ARGS__)
#define wxCALL_FOR_EACH_3(what, x, ...)   what(3, x)  wxCALL_FOR_EACH_2(what,  __VA_ARGS__)
#define wxCALL_FOR_EACH_4(what, x, ...)   what(4, x)  wxCALL_FOR_EACH_3(what,  __VA_ARGS__)
#define wxCALL_FOR_EACH_5(what, x, ...)   what(5, x)  wxCALL_FOR_EACH_4(what,  __VA_ARGS__)
#define wxCALL_FOR_EACH_6(what, x, ...)   what(6, x)  wxCALL_FOR_EACH_5(what,  __VA_ARGS__)
#define wxCALL_FOR_EACH_7(what, x, ...)   what(7, x)  wxCALL_FOR_EACH_6(what,  __VA_ARGS__)
#define wxCALL_FOR_EACH_8(what, x, ...)   what(8, x)  wxCALL_FOR_EACH_7(what,  __VA_ARGS__)

#define wxCALL_FOR_EACH_(N, args) \
    wxCONCAT(wxCALL_FOR_EACH_, N) args

#define wxCALL_FOR_EACH(what, ...) \
    wxCALL_FOR_EACH_(wxCALL_FOR_EACH_NARG(__VA_ARGS__), (what, __VA_ARGS__))

#else
    #define wxCALL_FOR_EACH  Error_wx_CALL_FOR_EACH_requires_variadic_macros_support
#endif /* wxHAS_VARIADIC_MACROS */

#endif /* _WX_CPP_H_ */
Commit	Line	Data
cdd8d745 VZ	1	/*
	2	* Name: wx/cpp.h
	3	* Purpose: Various preprocessor helpers
	4	* Author: Vadim Zeitlin
	5	* Created: 2006-09-30
	6	* RCS-ID: $Id$
	7	* Copyright: (c) 2006 Vadim Zeitlin <vadim@wxwindows.org>
	8	* Licence: wxWindows licence
	9	*/
	10
	11	/* THIS IS A C FILE, DON'T USE C++ FEATURES (IN PARTICULAR COMMENTS) IN IT */
	12
	13	#ifndef _WX_CPP_H_
	14	#define _WX_CPP_H_
	15
	16	/* wxCONCAT works like preprocessor ## operator but also works with macros */
	17	#define wxCONCAT_HELPER(text, line) text ## line
cdd8d745	18
47eab2f2 VZ	19	#define wxCONCAT(x1, x2) \
	20	wxCONCAT_HELPER(x1, x2)
	21	#define wxCONCAT3(x1, x2, x3) \
	22	wxCONCAT(wxCONCAT(x1, x2), x3)
	23	#define wxCONCAT4(x1, x2, x3, x4) \
	24	wxCONCAT(wxCONCAT3(x1, x2, x3), x4)
	25	#define wxCONCAT5(x1, x2, x3, x4, x5) \
	26	wxCONCAT(wxCONCAT4(x1, x2, x3, x4), x5)
	27	#define wxCONCAT6(x1, x2, x3, x4, x5, x6) \
	28	wxCONCAT(wxCONCAT5(x1, x2, x3, x4, x5), x6)
	29	#define wxCONCAT7(x1, x2, x3, x4, x5, x6, x7) \
	30	wxCONCAT(wxCONCAT6(x1, x2, x3, x4, x5, x6), x7)
	31	#define wxCONCAT8(x1, x2, x3, x4, x5, x6, x7, x8) \
	32	wxCONCAT(wxCONCAT7(x1, x2, x3, x4, x5, x6, x7), x8)
	33	#define wxCONCAT9(x1, x2, x3, x4, x5, x6, x7, x8, x9) \
	34	wxCONCAT(wxCONCAT8(x1, x2, x3, x4, x5, x6, x7, x8), x9)
1894e49f	35
cdd8d745 VZ	36	/* wxSTRINGIZE works as the preprocessor # operator but also works with macros */
	37	#define wxSTRINGIZE_HELPER(x) #x
	38	#define wxSTRINGIZE(x) wxSTRINGIZE_HELPER(x)
	39
84206bbb VZ	40	/* a Unicode-friendly version of wxSTRINGIZE_T */
	41	#define wxSTRINGIZE_T(x) wxAPPLY_T(wxSTRINGIZE(x))
	42
25859335 VZ	43	/*
	44	Special workarounds for compilers with broken "##" operator. For all the
	45	other ones we can just use it directly.
	46	*/
	47	#ifdef wxCOMPILER_BROKEN_CONCAT_OPER
	48	#define wxPREPEND_L(x) L ## x
	49	#define wxAPPEND_i64(x) x ## i64
	50	#define wxAPPEND_ui64(x) x ## ui64
	51	#endif /* wxCOMPILER_BROKEN_CONCAT_OPER */
	52
cdd8d745 VZ	53	/*
	54	Helper macros for wxMAKE_UNIQUE_NAME: normally this works by appending the
	55	current line number to the given identifier to reduce the probability of the
	56	conflict (it may still happen if this is used in the headers, hence you
	57	should avoid doing it or provide unique prefixes then) but we have to do it
	58	differently for VC++
	59	*/
	60	#if defined(__VISUALC__) && (__VISUALC__ >= 1300)
	61	/*
	62	__LINE__ handling is completely broken in VC++ when using "Edit and
	63	Continue" (/ZI option) and results in preprocessor errors if we use it
	64	inside the macros. Luckily VC7 has another standard macro which can be
	65	used like this and is even better than __LINE__ because it is globally
	66	unique.
	67	*/
	68	# define wxCONCAT_LINE(text) wxCONCAT(text, __COUNTER__)
	69	#else /* normal compilers */
	70	# define wxCONCAT_LINE(text) wxCONCAT(text, __LINE__)
	71	#endif
	72
	73	/* Create a "unique" name with the given prefix */
	74	#define wxMAKE_UNIQUE_NAME(text) wxCONCAT_LINE(text)
	75
bde626ce VZ	76	/*
	77	This macro can be passed as argument to another macro when you don't have
	78	anything to pass in fact.
	79	*/
	80	#define wxEMPTY_PARAMETER_VALUE /* Fake macro parameter value */
	81
4d3845c0 VZ	82	/*
	83	Helpers for defining macros that expand into a single statement.
	84
	85	The standatd solution is to use "do { ... } while (0)" statement but MSVC
	86	generates a C4127 "condition expression is constant" warning for it so we
	87	use something which is just complicated enough to not be recognized as a
	88	constant but still simple enough to be optimized away.
	89
	90	Another solution would be to use __pragma() to temporarily disable C4127.
	91
	92	Notice that wxASSERT_ARG_TYPE in wx/strvargarg.h relies on these macros
	93	creating some kind of a loop because it uses "break".
	94	*/
	95	#ifdef __WATCOMC__
	96	#define wxFOR_ONCE(name) for(int name=0; name<1; name++)
	97	#define wxSTATEMENT_MACRO_BEGIN wxFOR_ONCE(wxMAKE_UNIQUE_NAME(wxmacro)) {
	98	#define wxSTATEMENT_MACRO_END }
	99	#else
	100	#define wxSTATEMENT_MACRO_BEGIN do {
	101	#define wxSTATEMENT_MACRO_END } while ( (void)0, 0 )
	102	#endif
	103
a6ebdba6 VZ	104	/*
	105	Define __WXFUNCTION__ which is like standard __FUNCTION__ but defined as
	106	NULL for the compilers which don't support the latter.
	107	*/
	108	#ifndef __WXFUNCTION__
	109	/* TODO: add more compilers supporting __FUNCTION__ */
	110	#if defined(__DMC__)
	111	/*
	112	__FUNCTION__ happens to be not defined within class members
	113	http://www.digitalmars.com/drn-bin/wwwnews?c%2B%2B.beta/485
	114	*/
	115	#define __WXFUNCTION__ (NULL)
	116	#elif defined(__GNUC__) \|\| \
	117	(defined(_MSC_VER) && _MSC_VER >= 1300) \|\| \
	118	defined(__FUNCTION__)
	119	#define __WXFUNCTION__ __FUNCTION__
	120	#else
	121	/* still define __WXFUNCTION__ to avoid #ifdefs elsewhere */
	122	#define __WXFUNCTION__ (NULL)
	123	#endif
	124	#endif /* __WXFUNCTION__ already defined */
	125
a4d982a7 VS	126
	127	#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) \|\| \
	128	(defined(__cplusplus) && __cplusplus >= 201103L)
	129	#define wxHAS_VARIADIC_MACROS
	130	#elif defined(__GNUC__) && __GNUC__ >= 3
	131	#define wxHAS_VARIADIC_MACROS
	132	#elif defined(_MSC_VER) && _MSC_VER >= 1400
	133	#define wxHAS_VARIADIC_MACROS
	134	#endif
	135
	136	#ifdef wxHAS_VARIADIC_MACROS
	137	/*
	138	wxCALL_FOR_EACH(what, ...) calls the macro from its first argument, what(pos, x),
	139	for every remaining argument 'x', with 'pos' being its 1-based index in
	140	reverse order (with the last argument being numbered 1).
	141
	142	For example, wxCALL_FOR_EACH(test, a, b, c) expands into this:
	143
	144	test(3, a) \
	145	test(2, b) \
	146	test(1, c)
	147
	148	Up to eight arguments are supported.
	149
	150	(With thanks to https://groups.google.com/d/topic/comp.std.c/d-6Mj5Lko_s/discussion
	151	and http://stackoverflow.com/questions/1872220/is-it-possible-to-iterate-over-arguments-in-variadic-macros)
	152	*/
e08d449f VS	153	#define wxCALL_FOR_EACH_NARG(...) wxCALL_FOR_EACH_NARG_((__VA_ARGS__, wxCALL_FOR_EACH_RSEQ_N()))
e08d449f VS	154	#define wxCALL_FOR_EACH_NARG_(args) wxCALL_FOR_EACH_ARG_N args
a4d982a7 VS	155	#define wxCALL_FOR_EACH_ARG_N(_1, _2, _3, _4, _5, _6, _7, _8, N, ...) N
	156	#define wxCALL_FOR_EACH_RSEQ_N() 8, 7, 6, 5, 4, 3, 2, 1, 0
	157
	158	#define wxCALL_FOR_EACH_1(what, x) what(1, x)
	159	#define wxCALL_FOR_EACH_2(what, x, ...) what(2, x) wxCALL_FOR_EACH_1(what, __VA_ARGS__)
	160	#define wxCALL_FOR_EACH_3(what, x, ...) what(3, x) wxCALL_FOR_EACH_2(what, __VA_ARGS__)
	161	#define wxCALL_FOR_EACH_4(what, x, ...) what(4, x) wxCALL_FOR_EACH_3(what, __VA_ARGS__)
	162	#define wxCALL_FOR_EACH_5(what, x, ...) what(5, x) wxCALL_FOR_EACH_4(what, __VA_ARGS__)
	163	#define wxCALL_FOR_EACH_6(what, x, ...) what(6, x) wxCALL_FOR_EACH_5(what, __VA_ARGS__)
	164	#define wxCALL_FOR_EACH_7(what, x, ...) what(7, x) wxCALL_FOR_EACH_6(what, __VA_ARGS__)
	165	#define wxCALL_FOR_EACH_8(what, x, ...) what(8, x) wxCALL_FOR_EACH_7(what, __VA_ARGS__)
	166
e08d449f VS	167	#define wxCALL_FOR_EACH_(N, args) \
e08d449f VS	168	wxCONCAT(wxCALL_FOR_EACH_, N) args
a4d982a7 VS	169
a4d982a7 VS	170	#define wxCALL_FOR_EACH(what, ...) \
e08d449f	171	wxCALL_FOR_EACH_(wxCALL_FOR_EACH_NARG(__VA_ARGS__), (what, __VA_ARGS__))
a4d982a7 VS	172
	173	#else
	174	#define wxCALL_FOR_EACH Error_wx_CALL_FOR_EACH_requires_variadic_macros_support
	175	#endif /* wxHAS_VARIADIC_MACROS */
	176
28efe654	177	#endif /* _WX_CPP_H_ */
cdd8d745	178