1 /* 2 * Name: wx/cpp.h 3 * Purpose: Various preprocessor helpers 4 * Author: Vadim Zeitlin 5 * Created: 2006-09-30 6 * Copyright: (c) 2006 Vadim Zeitlin <vadim@wxwindows.org> 7 * Licence: wxWindows licence 8 */ 9 10 /* THIS IS A C FILE, DON'T USE C++ FEATURES (IN PARTICULAR COMMENTS) IN IT */ 11 12 #ifndef _WX_CPP_H_ 13 #define _WX_CPP_H_ 14 15 #include "wx/compiler.h" /* wxCHECK_XXX_VERSION() macros */ 16 17 /* wxCONCAT works like preprocessor ## operator but also works with macros */ 18 #define wxCONCAT_HELPER(text, line) text ## line 19 20 #define wxCONCAT(x1, x2) \ 21 wxCONCAT_HELPER(x1, x2) 22 #define wxCONCAT3(x1, x2, x3) \ 23 wxCONCAT(wxCONCAT(x1, x2), x3) 24 #define wxCONCAT4(x1, x2, x3, x4) \ 25 wxCONCAT(wxCONCAT3(x1, x2, x3), x4) 26 #define wxCONCAT5(x1, x2, x3, x4, x5) \ 27 wxCONCAT(wxCONCAT4(x1, x2, x3, x4), x5) 28 #define wxCONCAT6(x1, x2, x3, x4, x5, x6) \ 29 wxCONCAT(wxCONCAT5(x1, x2, x3, x4, x5), x6) 30 #define wxCONCAT7(x1, x2, x3, x4, x5, x6, x7) \ 31 wxCONCAT(wxCONCAT6(x1, x2, x3, x4, x5, x6), x7) 32 #define wxCONCAT8(x1, x2, x3, x4, x5, x6, x7, x8) \ 33 wxCONCAT(wxCONCAT7(x1, x2, x3, x4, x5, x6, x7), x8) 34 #define wxCONCAT9(x1, x2, x3, x4, x5, x6, x7, x8, x9) \ 35 wxCONCAT(wxCONCAT8(x1, x2, x3, x4, x5, x6, x7, x8), x9) 36 37 /* wxSTRINGIZE works as the preprocessor # operator but also works with macros */ 38 #define wxSTRINGIZE_HELPER(x) #x 39 #define wxSTRINGIZE(x) wxSTRINGIZE_HELPER(x) 40 41 /* a Unicode-friendly version of wxSTRINGIZE_T */ 42 #define wxSTRINGIZE_T(x) wxAPPLY_T(wxSTRINGIZE(x)) 43 44 /* 45 Special workarounds for compilers with broken "##" operator. For all the 46 other ones we can just use it directly. 47 */ 48 #ifdef wxCOMPILER_BROKEN_CONCAT_OPER 49 #define wxPREPEND_L(x) L ## x 50 #define wxAPPEND_i64(x) x ## i64 51 #define wxAPPEND_ui64(x) x ## ui64 52 #endif /* wxCOMPILER_BROKEN_CONCAT_OPER */ 53 54 /* 55 Helper macros for wxMAKE_UNIQUE_NAME: normally this works by appending the 56 current line number to the given identifier to reduce the probability of the 57 conflict (it may still happen if this is used in the headers, hence you 58 should avoid doing it or provide unique prefixes then) but we have to do it 59 differently for VC++ 60 */ 61 #if defined(__VISUALC__) && (__VISUALC__ >= 1300) 62 /* 63 __LINE__ handling is completely broken in VC++ when using "Edit and 64 Continue" (/ZI option) and results in preprocessor errors if we use it 65 inside the macros. Luckily VC7 has another standard macro which can be 66 used like this and is even better than __LINE__ because it is globally 67 unique. 68 */ 69 # define wxCONCAT_LINE(text) wxCONCAT(text, __COUNTER__) 70 #else /* normal compilers */ 71 # define wxCONCAT_LINE(text) wxCONCAT(text, __LINE__) 72 #endif 73 74 /* Create a "unique" name with the given prefix */ 75 #define wxMAKE_UNIQUE_NAME(text) wxCONCAT_LINE(text) 76 77 /* 78 This macro can be passed as argument to another macro when you don't have 79 anything to pass in fact. 80 */ 81 #define wxEMPTY_PARAMETER_VALUE /* Fake macro parameter value */ 82 83 /* 84 Helpers for defining macros that expand into a single statement. 85 86 The standatd solution is to use "do { ... } while (0)" statement but MSVC 87 generates a C4127 "condition expression is constant" warning for it so we 88 use something which is just complicated enough to not be recognized as a 89 constant but still simple enough to be optimized away. 90 91 Another solution would be to use __pragma() to temporarily disable C4127. 92 93 Notice that wxASSERT_ARG_TYPE in wx/strvargarg.h relies on these macros 94 creating some kind of a loop because it uses "break". 95 */ 96 #ifdef __WATCOMC__ 97 #define wxFOR_ONCE(name) for(int name=0; name<1; name++) 98 #define wxSTATEMENT_MACRO_BEGIN wxFOR_ONCE(wxMAKE_UNIQUE_NAME(wxmacro)) { 99 #define wxSTATEMENT_MACRO_END } 100 #else 101 #define wxSTATEMENT_MACRO_BEGIN do { 102 #define wxSTATEMENT_MACRO_END } while ( (void)0, 0 ) 103 #endif 104 105 /* 106 Define __WXFUNCTION__ which is like standard __FUNCTION__ but defined as 107 NULL for the compilers which don't support the latter. 108 */ 109 #ifndef __WXFUNCTION__ 110 /* TODO: add more compilers supporting __FUNCTION__ */ 111 #if defined(__DMC__) 112 /* 113 __FUNCTION__ happens to be not defined within class members 114 http://www.digitalmars.com/drn-bin/wwwnews?c%2B%2B.beta/485 115 */ 116 #define __WXFUNCTION__ (NULL) 117 #elif defined(__GNUC__) || \ 118 (defined(_MSC_VER) && _MSC_VER >= 1300) || \ 119 defined(__FUNCTION__) 120 #define __WXFUNCTION__ __FUNCTION__ 121 #else 122 /* still define __WXFUNCTION__ to avoid #ifdefs elsewhere */ 123 #define __WXFUNCTION__ (NULL) 124 #endif 125 #endif /* __WXFUNCTION__ already defined */ 126 127 128 /* Auto-detect variadic macros support unless explicitly disabled. */ 129 #if !defined(HAVE_VARIADIC_MACROS) && !defined(wxNO_VARIADIC_MACROS) 130 /* Any C99 or C++11 compiler should have them. */ 131 #if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || \ 132 (defined(__cplusplus) && __cplusplus >= 201103L) 133 #define HAVE_VARIADIC_MACROS 134 #elif wxCHECK_GCC_VERSION(3,0) 135 #define HAVE_VARIADIC_MACROS 136 #elif wxCHECK_VISUALC_VERSION(8) 137 #define HAVE_VARIADIC_MACROS 138 #elif wxCHECK_WATCOM_VERSION(1,2) 139 #define HAVE_VARIADIC_MACROS 140 #endif 141 #endif /* !HAVE_VARIADIC_MACROS */ 142 143 144 145 #ifdef HAVE_VARIADIC_MACROS 146 /* 147 wxCALL_FOR_EACH(what, ...) calls the macro from its first argument, what(pos, x), 148 for every remaining argument 'x', with 'pos' being its 1-based index in 149 *reverse* order (with the last argument being numbered 1). 150 151 For example, wxCALL_FOR_EACH(test, a, b, c) expands into this: 152 153 test(3, a) \ 154 test(2, b) \ 155 test(1, c) 156 157 Up to eight arguments are supported. 158 159 (With thanks to https://groups.google.com/d/topic/comp.std.c/d-6Mj5Lko_s/discussion 160 and http://stackoverflow.com/questions/1872220/is-it-possible-to-iterate-over-arguments-in-variadic-macros) 161 */ 162 #define wxCALL_FOR_EACH_NARG(...) wxCALL_FOR_EACH_NARG_((__VA_ARGS__, wxCALL_FOR_EACH_RSEQ_N())) 163 #define wxCALL_FOR_EACH_NARG_(args) wxCALL_FOR_EACH_ARG_N args 164 #define wxCALL_FOR_EACH_ARG_N(_1, _2, _3, _4, _5, _6, _7, _8, N, ...) N 165 #define wxCALL_FOR_EACH_RSEQ_N() 8, 7, 6, 5, 4, 3, 2, 1, 0 166 167 #define wxCALL_FOR_EACH_1(what, x) what(1, x) 168 #define wxCALL_FOR_EACH_2(what, x, ...) what(2, x) wxCALL_FOR_EACH_1(what, __VA_ARGS__) 169 #define wxCALL_FOR_EACH_3(what, x, ...) what(3, x) wxCALL_FOR_EACH_2(what, __VA_ARGS__) 170 #define wxCALL_FOR_EACH_4(what, x, ...) what(4, x) wxCALL_FOR_EACH_3(what, __VA_ARGS__) 171 #define wxCALL_FOR_EACH_5(what, x, ...) what(5, x) wxCALL_FOR_EACH_4(what, __VA_ARGS__) 172 #define wxCALL_FOR_EACH_6(what, x, ...) what(6, x) wxCALL_FOR_EACH_5(what, __VA_ARGS__) 173 #define wxCALL_FOR_EACH_7(what, x, ...) what(7, x) wxCALL_FOR_EACH_6(what, __VA_ARGS__) 174 #define wxCALL_FOR_EACH_8(what, x, ...) what(8, x) wxCALL_FOR_EACH_7(what, __VA_ARGS__) 175 176 #define wxCALL_FOR_EACH_(N, args) \ 177 wxCONCAT(wxCALL_FOR_EACH_, N) args 178 179 #define wxCALL_FOR_EACH(what, ...) \ 180 wxCALL_FOR_EACH_(wxCALL_FOR_EACH_NARG(__VA_ARGS__), (what, __VA_ARGS__)) 181 182 #else 183 #define wxCALL_FOR_EACH Error_wx_CALL_FOR_EACH_requires_variadic_macros_support 184 #endif /* HAVE_VARIADIC_MACROS */ 185 186 #endif /* _WX_CPP_H_ */ 187 188