include/wx/debug.h

   1 /**
   2 *  Name:        wx/debug.h
   3 *  Purpose:     Misc debug functions and macros
   4 *  Author:      Vadim Zeitlin
   5 *  Modified by: Ryan Norton (Converted to C)
   6 *  Created:     29/01/98
   7 *  RCS-ID:      $Id$
   8 *  Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
   9 *  Licence:     wxWindows licence
  10 */
  11
  12 /* THIS IS A C FILE, DON'T USE C++ FEATURES (IN PARTICULAR COMMENTS) IN IT */
  13
  14 #ifndef   _WX_DEBUG_H_
  15 #define   _WX_DEBUG_H_
  16
  17 #ifndef __WXWINCE__
  18 #include  <assert.h>
  19 #endif
  20 #include  <limits.h>            /*  for CHAR_BIT used below */
  21
  22 #include  "wx/wxchar.h"         /*  for __TFILE__ and wxChar */
  23
  24 /*  ---------------------------------------------------------------------------- */
  25 /*  Defines controlling the debugging macros */
  26 /*  ---------------------------------------------------------------------------- */
  27
  28 /*  if _DEBUG is defined (MS VC++ and others use it in debug builds), define */
  29 /*  __WXDEBUG__ too */
  30 #ifdef _DEBUG
  31     #ifndef __WXDEBUG__
  32         #define __WXDEBUG__
  33     #endif /*  !__WXDEBUG__ */
  34 #endif /*  _DEBUG */
  35
  36 /*  if NDEBUG is defined (<assert.h> uses it), undef __WXDEBUG__ and WXDEBUG */
  37 #ifdef NDEBUG
  38     #undef __WXDEBUG__
  39     #undef WXDEBUG
  40 #endif /*  NDEBUG */
  41
  42 /*  if __WXDEBUG__ is defined, make sure that WXDEBUG is defined and >= 1 */
  43 #ifdef __WXDEBUG__
  44     #if !defined(WXDEBUG) || !WXDEBUG
  45         #undef WXDEBUG
  46         #define WXDEBUG 1
  47     #endif /*  !WXDEBUG */
  48 #endif /*  __WXDEBUG__ */
  49
  50 /*  ---------------------------------------------------------------------------- */
  51 /*  Debugging macros */
  52 /*  */
  53 /*  All debugging macros rely on ASSERT() which in turn calls user-defined */
  54 /*  OnAssert() function. To keep things simple, it's called even when the */
  55 /*  expression is true (i.e. everything is ok) and by default does nothing: just */
  56 /*  returns the same value back. But if you redefine it to do something more sexy */
  57 /*  (popping up a message box in your favourite GUI, sending you e-mail or */
  58 /*  whatever) it will affect all ASSERTs, FAILs and CHECKs in your code. */
  59 /*  */
  60 /*  Warning: if you don't like advice on programming style, don't read */
  61 /*  further! ;-) */
  62 /*  */
  63 /*  Extensive use of these macros is recommended! Remember that ASSERTs are */
  64 /*  disabled in final build (without __WXDEBUG__ defined), so they add strictly */
  65 /*  nothing to your program's code. On the other hand, CHECK macros do stay */
  66 /*  even in release builds, but in general are not much of a burden, while */
  67 /*  a judicious use of them might increase your program's stability. */
  68 /*  ---------------------------------------------------------------------------- */
  69
  70 /*  Macros which are completely disabled in 'release' mode */
  71 /*  */
  72 /*  NB: these functions are implemented in src/common/appcmn.cpp */
  73 #if defined(__cplusplus) && defined(__WXDEBUG__)
  74   /*
  75     this function may be redefined to do something non trivial and is called
  76     whenever one of debugging macros fails (i.e. condition is false in an
  77     assertion)
  78
  79     parameters:
  80        szFile and nLine - file name and line number of the ASSERT
  81        szMsg            - optional message explaining the reason
  82   */
  83   extern void WXDLLIMPEXP_BASE wxOnAssert(const wxChar *szFile,
  84                                           int nLine,
  85                                           const wxChar *szCond,
  86                                           const wxChar *szMsg = NULL);
  87
  88   /*  call this function to break into the debugger unconditionally (assuming */
  89   /*  the program is running under debugger, of course) */
  90   extern void WXDLLIMPEXP_BASE wxTrap();
  91
  92   /*  helper function used to implement wxASSERT and wxASSERT_MSG */
  93   /*  */
  94   /*  note using "int" and not "bool" for cond to avoid VC++ warnings about */
  95   /*  implicit conversions when doing "wxAssert( pointer )" and also use of */
  96   /*  "!!cond" below to ensure that everything is converted to int */
  97   extern void WXDLLIMPEXP_BASE wxAssert(int cond,
  98                                         const wxChar *szFile,
  99                                         int nLine,
 100                                         const wxChar *szCond,
 101                                         const wxChar *szMsg = NULL) ;
 102
 103   /*  generic assert macro */
 104   #define wxASSERT(cond) wxAssert(!!(cond), __TFILE__, __LINE__, _T(#cond))
 105
 106   /*  assert with additional message explaining it's cause */
 107   #define wxASSERT_MSG(cond, msg) \
 108     wxAssert(!!(cond), __TFILE__, __LINE__, _T(#cond), msg)
 109
 110   /*  an assert helper used to avoid warning when testing constant expressions, */
 111   /*  i.e. wxASSERT( sizeof(int) == 4 ) can generate a compiler warning about */
 112   /*  expression being always true, but not using */
 113   /*  wxASSERT( wxAssertIsEqual(sizeof(int), 4) ) */
 114   /*  */
 115   /*  NB: this is made obsolete by wxCOMPILE_TIME_ASSERT() and shouldn't be */
 116   /*      used any longer */
 117   extern bool WXDLLIMPEXP_BASE wxAssertIsEqual(int x, int y);
 118 #else
 119   #define wxTrap()
 120
 121   /*  nothing to do in release modes (hopefully at this moment there are */
 122   /*  no more bugs ;-) */
 123   #define wxASSERT(cond)
 124   #define wxASSERT_MSG(x, m)
 125 #endif  /* __WXDEBUG__ */
 126
 127 #ifdef __cplusplus
 128     /*  Use of wxFalse instead of false suppresses compiler warnings about testing */
 129     /*  constant expression */
 130     WXDLLIMPEXP_DATA_BASE(extern const bool) wxFalse;
 131 #endif
 132
 133 #define wxAssertFailure wxFalse
 134
 135 /*  special form of assert: always triggers it (in debug mode) */
 136 #define wxFAIL                 wxASSERT(wxAssertFailure)
 137
 138 /*  FAIL with some message */
 139 #define wxFAIL_MSG(msg)        wxASSERT_MSG(wxAssertFailure, msg)
 140
 141 /*  NB: the following macros work also in release mode! */
 142
 143 /*
 144   These macros must be used only in invalid situation: for example, an
 145   invalid parameter (NULL pointer) is passed to a function. Instead of
 146   dereferencing it and causing core dump the function might try using
 147   CHECK( p != NULL ) or CHECK( p != NULL, return LogError("p is NULL!!") )
 148 */
 149
 150 /*  check that expression is true, "return" if not (also FAILs in debug mode) */
 151 #define wxCHECK(x, rc)            if (!(x)) {wxFAIL; return rc; }
 152
 153 /*  as wxCHECK but with a message explaining why we fail */
 154 #define wxCHECK_MSG(x, rc, msg)   if (!(x)) {wxFAIL_MSG(msg); return rc; }
 155
 156 /*  check that expression is true, perform op if not */
 157 #define wxCHECK2(x, op)           if (!(x)) {wxFAIL; op; }
 158
 159 /*  as wxCHECK2 but with a message explaining why we fail */
 160 #define wxCHECK2_MSG(x, op, msg)  if (!(x)) {wxFAIL_MSG(msg); op; }
 161
 162 /*  special form of wxCHECK2: as wxCHECK, but for use in void functions */
 163 /*  */
 164 /*  NB: there is only one form (with msg parameter) and it's intentional: */
 165 /*      there is no other way to tell the caller what exactly went wrong */
 166 /*      from the void function (of course, the function shouldn't be void */
 167 /*      to begin with...) */
 168 #define wxCHECK_RET(x, msg)       if (!(x)) {wxFAIL_MSG(msg); return; }
 169
 170 /*  ---------------------------------------------------------------------------- */
 171 /*  Compile time asserts */
 172 /*  */
 173 /*  Unlike the normal assert and related macros above which are checked during */
 174 /*  the program tun-time the macros below will result in a compilation error if */
 175 /*  the condition they check is false. This is usually used to check the */
 176 /*  expressions containing sizeof()s which cannot be tested with the */
 177 /*  preprocessor. If you can use the #if's, do use them as you can give a more */
 178 /*  detailed error message then. */
 179 /*  ---------------------------------------------------------------------------- */
 180
 181 /*
 182   How this works (you don't have to understand it to be able to use the
 183   macros): we rely on the fact that it is invalid to define a named bit field
 184   in a struct of width 0. All the rest are just the hacks to minimize the
 185   possibility of the compiler warnings when compiling this macro: in
 186   particular, this is why we define a struct and not an object (which would
 187   result in a warning about unused variable) and a named struct (otherwise we'd
 188   get a warning about an unnamed struct not used to define an object!).
 189  */
 190
 191 #define wxMAKE_UNIQUE_ASSERT_NAME           wxMAKE_UNIQUE_NAME(wxAssert_)
 192
 193 /*
 194   The second argument of this macro must be a valid C++ identifier and not a
 195   string. I.e. you should use it like this:
 196
 197     wxCOMPILE_TIME_ASSERT( sizeof(int) >= 2, YourIntsAreTooSmall );
 198
 199  It may be used both within a function and in the global scope.
 200 */
 201 #ifdef __WATCOMC__
 202     /* avoid "unused symbol" warning */
 203     #define wxCOMPILE_TIME_ASSERT(expr, msg) \
 204         class wxMAKE_UNIQUE_ASSERT_NAME { \
 205           unsigned int msg: expr; \
 206           wxMAKE_UNIQUE_ASSERT_NAME() { wxUnusedVar(msg); } \
 207         }
 208 #else
 209     #define wxCOMPILE_TIME_ASSERT(expr, msg) \
 210         struct wxMAKE_UNIQUE_ASSERT_NAME { unsigned int msg: expr; }
 211 #endif
 212
 213 /*
 214    When using VC++ 6 with "Edit and Continue" on, the compiler completely
 215    mishandles __LINE__ and so wxCOMPILE_TIME_ASSERT() doesn't work, provide a
 216    way to make "unique" assert names by specifying a unique prefix explicitly
 217  */
 218 #define wxMAKE_UNIQUE_ASSERT_NAME2(text) wxCONCAT(wxAssert_, text)
 219
 220 #ifdef __WATCOMC__
 221     /* avoid "unused symbol" warning */
 222     #define wxCOMPILE_TIME_ASSERT2(expr, msg, text) \
 223         class wxMAKE_UNIQUE_ASSERT_NAME2(text) { \
 224           unsigned int msg: expr; \
 225           wxMAKE_UNIQUE_ASSERT_NAME2(text) { wxUnusedVar(msg); } \
 226         }
 227 #else
 228     #define wxCOMPILE_TIME_ASSERT2(expr, msg, text) \
 229         struct wxMAKE_UNIQUE_ASSERT_NAME2(text) { unsigned int msg: expr; }
 230 #endif
 231
 232 /*  helpers for wxCOMPILE_TIME_ASSERT below, for private use only */
 233 #define wxMAKE_BITSIZE_MSG(type, size) type ## SmallerThan ## size ## Bits
 234
 235 /*  a special case of compile time assert: check that the size of the given type */
 236 /*  is at least the given number of bits */
 237 #define wxASSERT_MIN_BITSIZE(type, size) \
 238     wxCOMPILE_TIME_ASSERT(sizeof(type) * CHAR_BIT >= size, \
 239                           wxMAKE_BITSIZE_MSG(type, size))
 240
 241 /*  ---------------------------------------------------------------------------- */
 242 /*  other miscellaneous debugger-related functions */
 243 /*  ---------------------------------------------------------------------------- */
 244
 245 /*  return true if we're running under debugger */
 246 /*  */
 247 /*  currently this only really works under Mac in CodeWarrior builds, it always */
 248 /*  returns false otherwise */
 249 #ifdef __cplusplus
 250     #ifdef __WXMAC__
 251         extern bool WXDLLIMPEXP_BASE wxIsDebuggerRunning();
 252     #else /*  !Mac */
 253         inline bool wxIsDebuggerRunning() { return false; }
 254     #endif /*  Mac/!Mac */
 255 #endif /* __cplusplus */
 256
 257 #endif  /*  _WX_DEBUG_H_ */
 258