added and documented wx_const/static_cast<>

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

diff --git a/include/wx/debug.h b/include/wx/debug.h
index 5ccea5af0fdda1a1e1b44e5d2048f0cd43d49770..f353646e8bb46eff5c88805de1fa1a5b8cc5acdf 100644 (file)
--- a/include/wx/debug.h
+++ b/include/wx/debug.h
@@ -1,103 +1,240 @@
-/////////////////////////////////////////////////////////////////////////////
-// Name:        debug.h
-// Purpose:     Misc debug functions and macros
-// Author:      Vadim Zeitlin
-// Modified by:
-// Created:     29/01/98
-// RCS-ID:      $Id$
-// Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
-// Licence:    wxWindows license
-/////////////////////////////////////////////////////////////////////////////
+/**
+*  Name:        wx/debug.h 
+*  Purpose:     Misc debug functions and macros 
+*  Author:      Vadim Zeitlin 
+*  Modified by: Ryan Norton (Converted to C)
+*  Created:     29/01/98 
+*  RCS-ID:      $Id$ 
+*  Copyright:   (c) 1998 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr> 
+*  Licence:     wxWindows licence 
+*/
+
+/* THIS IS A C FILE, DON'T USE C++ FEATURES (IN PARTICULAR COMMENTS) IN IT */

 
 #ifndef   _WX_DEBUG_H_
 #define   _WX_DEBUG_H_
 
 
 #ifndef   _WX_DEBUG_H_
 #define   _WX_DEBUG_H_
 

+#ifndef __WXWINCE__

 #include  <assert.h>
 #include  <assert.h>

+#endif
+#include  <limits.h>            /*  for CHAR_BIT used below */

 
 

-// ----------------------------------------------------------------------------
-/** 
-  @name Debugging macros 
-
-  All debugging macros rely on ASSERT() which in turn calls user-defined
-  OnAssert() function. To keep things simple, it's called even when the
-  expression is TRUE (i.e. everything is ok) and by default does nothing: just
-  returns the same value back. But if you redefine it to do something more sexy
-  (popping up a message box in your favourite GUI, sending you e-mail or 
-  whatever) it will affect all ASSERTs, FAILs and CHECKs in your code.
-  <BR>
-  <BR>
-  <b>Warning</b>: if you don't like advices on programming style, don't read 
-  further! ;-)
-  <BR>
-  <BR>
-  Extensive use of these macros is recommended! Remember that ASSERTs are
-  disabled in final (without __WXDEBUG__ defined) build, so they add strictly
-  nothing to your program's code. On the other hand, CHECK macros do stay
-  even in release builds, but in general are not much of a burden, while
-  a judicious use of them might increase your program's stability.
-
-  @memo Debugging macros (replacement for standard assert()) and more.
-  */
-// ----------------------------------------------------------------------------
-//@{
-
-/** @name Macros which are completely disabled in 'release' mode */
-//@{
-#ifdef  __WXDEBUG__
-  /**
-  this function may be redefined to do something non trivial and is called
-  whenever one of debugging macros fails (i.e. condition is false in an
-  assertion)
-  @param   szFile and nLine - file name and line number of the ASSERT
-           szMsg            - optional message explaining the reason
+#include  "wx/wxchar.h"         /*  for __TFILE__ and wxChar */
+
+/*  ---------------------------------------------------------------------------- */
+/*  Defines controlling the debugging macros */
+/*  ---------------------------------------------------------------------------- */
+
+/*  if _DEBUG is defined (MS VC++ and others use it in debug builds), define */
+/*  __WXDEBUG__ too */
+#ifdef _DEBUG
+    #ifndef __WXDEBUG__
+        #define __WXDEBUG__
+    #endif /*  !__WXDEBUG__ */
+#endif /*  _DEBUG */
+
+/*  if NDEBUG is defined (<assert.h> uses it), undef __WXDEBUG__ and WXDEBUG */
+#ifdef NDEBUG
+    #undef __WXDEBUG__
+    #undef WXDEBUG
+#endif /*  NDEBUG */
+
+/*  if __WXDEBUG__ is defined, make sure that WXDEBUG is defined and >= 1 */
+#ifdef __WXDEBUG__
+    #if !defined(WXDEBUG) || !WXDEBUG
+        #undef WXDEBUG
+        #define WXDEBUG 1
+    #endif /*  !WXDEBUG */
+#endif /*  __WXDEBUG__ */
+
+/*  ---------------------------------------------------------------------------- */
+/*  Debugging macros */
+/*  */
+/*  All debugging macros rely on ASSERT() which in turn calls user-defined */
+/*  OnAssert() function. To keep things simple, it's called even when the */
+/*  expression is TRUE (i.e. everything is ok) and by default does nothing: just */
+/*  returns the same value back. But if you redefine it to do something more sexy */
+/*  (popping up a message box in your favourite GUI, sending you e-mail or */
+/*  whatever) it will affect all ASSERTs, FAILs and CHECKs in your code. */
+/*  */
+/*  Warning: if you don't like advice on programming style, don't read */
+/*  further! ;-) */
+/*  */
+/*  Extensive use of these macros is recommended! Remember that ASSERTs are */
+/*  disabled in final build (without __WXDEBUG__ defined), so they add strictly */
+/*  nothing to your program's code. On the other hand, CHECK macros do stay */
+/*  even in release builds, but in general are not much of a burden, while */
+/*  a judicious use of them might increase your program's stability. */
+/*  ---------------------------------------------------------------------------- */
+
+/*  Macros which are completely disabled in 'release' mode */
+/*  */
+/*  NB: these functions are implemented in src/common/appcmn.cpp */
+#if defined(__cplusplus) && defined(__WXDEBUG__)
+  /*
+    this function may be redefined to do something non trivial and is called
+    whenever one of debugging macros fails (i.e. condition is false in an
+    assertion)
+
+    parameters:
+       szFile and nLine - file name and line number of the ASSERT
+       szMsg            - optional message explaining the reason

   */
   */

-  void WXDLLEXPORT wxOnAssert(const char *szFile, int nLine, const char *szMsg = (const char *) NULL);
+  extern void WXDLLIMPEXP_BASE wxOnAssert(const wxChar *szFile,
+                                          int nLine,
+                                          const wxChar *szCond,
+                                          const wxChar *szMsg = NULL);
+
+  /*  call this function to break into the debugger unconditionally (assuming */
+  /*  the program is running under debugger, of course) */
+  extern void WXDLLIMPEXP_BASE wxTrap();
+
+  /*  helper function used to implement wxASSERT and wxASSERT_MSG */
+  /*  */
+  /*  note using "int" and not "bool" for cond to avoid VC++ warnings about */
+  /*  implicit conversions when doing "wxAssert( pointer )" and also use of */
+  /*  "!!cond" below to ensure that everything is converted to int */
+  extern void WXDLLIMPEXP_BASE wxAssert(int cond,
+                                        const wxChar *szFile,
+                                        int nLine,
+                                        const wxChar *szCond,
+                                        const wxChar *szMsg = NULL) ;
+
+  /*  generic assert macro */
+  #define wxASSERT(cond) wxAssert(!!(cond), __TFILE__, __LINE__, _T(#cond))
+
+  /*  assert with additional message explaining it's cause */
+  #define wxASSERT_MSG(cond, msg) \
+    wxAssert(!!(cond), __TFILE__, __LINE__, _T(#cond), msg)

 
 

-  /// generic assert macro
-  #define   wxASSERT(cond)   if ( !(cond) ) wxOnAssert(__FILE__, __LINE__)
-  /// assert with additional message explaining it's cause 
-  #define   wxASSERT_MSG(x, m)  if ( !(x) ) wxOnAssert(__FILE__, __LINE__, m)
+  /*  an assert helper used to avoid warning when testing constant expressions, */
+  /*  i.e. wxASSERT( sizeof(int) == 4 ) can generate a compiler warning about */
+  /*  expression being always true, but not using */
+  /*  wxASSERT( wxAssertIsEqual(sizeof(int), 4) ) */
+  /*  */
+  /*  NB: this is made obsolete by wxCOMPILE_TIME_ASSERT() and shouldn't be */
+  /*      used any longer */
+  extern bool WXDLLIMPEXP_BASE wxAssertIsEqual(int x, int y);

 #else
 #else

-  // nothing to do in release modes (hopefully at this moment there are
-  // no more bugs ;-)
-  #define   wxASSERT(cond)
-  #define   wxASSERT_MSG(x, m)
-#endif  //__WXDEBUG__
+  #define wxTrap()
+
+  /*  nothing to do in release modes (hopefully at this moment there are */
+  /*  no more bugs ;-) */
+  #define wxASSERT(cond)
+  #define wxASSERT_MSG(x, m)
+#endif  /* __WXDEBUG__ */
+
+#ifdef __cplusplus
+    /*  Use of wxFalse instead of FALSE suppresses compiler warnings about testing */
+    /*  constant expression */
+    WXDLLIMPEXP_DATA_BASE(extern const bool) wxFalse;
+#endif
+
+#define wxAssertFailure wxFalse
+
+/*  special form of assert: always triggers it (in debug mode) */
+#define wxFAIL                 wxASSERT(wxAssertFailure)

 
 

-  /// special form of assert: always triggers it (in debug mode)
-#define   wxFAIL                 wxASSERT(wxFalse)
-  /// FAIL with some message
-#define   wxFAIL_MSG(msg)        wxASSERT_MSG(wxFalse, msg)
-//@}
+/*  FAIL with some message */
+#define wxFAIL_MSG(msg)        wxASSERT_MSG(wxAssertFailure, msg)

 
 

-// NB: these macros work also in release mode!
+/*  NB: the following macros work also in release mode! */

 
 

-/** 
+/*

   These macros must be used only in invalid situation: for example, an
   invalid parameter (NULL pointer) is passed to a function. Instead of
   dereferencing it and causing core dump the function might try using
   CHECK( p != NULL ) or CHECK( p != NULL, return LogError("p is NULL!!") )
   These macros must be used only in invalid situation: for example, an
   invalid parameter (NULL pointer) is passed to a function. Instead of
   dereferencing it and causing core dump the function might try using
   CHECK( p != NULL ) or CHECK( p != NULL, return LogError("p is NULL!!") )

+*/
+
+/*  check that expression is true, "return" if not (also FAILs in debug mode) */
+#define wxCHECK(x, rc)            if (!(x)) {wxFAIL; return rc; }
+
+/*  as wxCHECK but with a message explaining why we fail */
+#define wxCHECK_MSG(x, rc, msg)   if (!(x)) {wxFAIL_MSG(msg); return rc; }
+
+/*  check that expression is true, perform op if not */
+#define wxCHECK2(x, op)           if (!(x)) {wxFAIL; op; }
+
+/*  as wxCHECK2 but with a message explaining why we fail */
+#define wxCHECK2_MSG(x, op, msg)  if (!(x)) {wxFAIL_MSG(msg); op; }
+
+/*  special form of wxCHECK2: as wxCHECK, but for use in void functions */
+/*  */
+/*  NB: there is only one form (with msg parameter) and it's intentional: */
+/*      there is no other way to tell the caller what exactly went wrong */
+/*      from the void function (of course, the function shouldn't be void */
+/*      to begin with...) */
+#define wxCHECK_RET(x, msg)       if (!(x)) {wxFAIL_MSG(msg); return; }
+
+/*  ---------------------------------------------------------------------------- */
+/*  Compile time asserts */
+/*  */
+/*  Unlike the normal assert and related macros above which are checked during */
+/*  the program tun-time the macros below will result in a compilation error if */
+/*  the condition they check is false. This is usually used to check the */
+/*  expressions containing sizeof()s which cannot be tested with the */
+/*  preprocessor. If you can use the #if's, do use them as you can give a more */
+/*  detailed error message then. */
+/*  ---------------------------------------------------------------------------- */
+
+/*
+  How this works (you don't have to understand it to be able to use the
+  macros): we rely on the fact that it is invalid to define a named bit field
+  in a struct of width 0. All the rest are just the hacks to minimize the
+  possibility of the compiler warnings when compiling this macro: in
+  particular, this is why we define a struct and not an object (which would
+  result in a warning about unused variable) and a named struct (otherwise we'd
+  get a warning about an unnamed struct not used to define an object!).
+ */
+
+#define wxMAKE_UNIQUE_ASSERT_NAME           wxMAKE_UNIQUE_NAME(wxAssert_)

 
 

-  @name Macros which remain even in 'release' mode 
+/*
+  The second argument of this macro must be a valid C++ identifier and not a
+  string. I.e. you should use it like this:
+
+    wxCOMPILE_TIME_ASSERT( sizeof(int) >= 2, YourIntsAreTooSmall );
+
+ It may be used both within a function and in the global scope.

 */
 */

-//@{
-  /// check that expression is true, "return" if not (also FAILs in debug mode)
-#define   wxCHECK(x, rc)            if (!(x)) {wxFAIL; return rc; }
-  /// as wxCHECK but with a message explaining why we fail
-#define   wxCHECK_MSG(x, rc, msg)   if (!(x)) {wxFAIL_MSG(msg); return rc; }
-  /// check that expression is true, perform op if not
-#define   wxCHECK2(x, op)           if (!(x)) {wxFAIL; op; }
-  /// as wxCHECK2 but with a message explaining why we fail
-#define   wxCHECK2_MSG(x, op, msg)  if (!(x)) {wxFAIL_MSG(msg); op; }
-  /// special form of wxCHECK2: as wxCHECK, but for use in void functions
-  //  NB: there is only one form (with msg parameter) and it's intentional:
-  //      there is no other way to tell the caller what exactly went wrong
-  //      from the void function (of course, the function shouldn't be void
-  //      to begin with...)
-#define   wxCHECK_RET(x, msg)       if (!(x)) {wxFAIL_MSG(msg); return; }
-//@}
-
-//@}
-
-#endif  // _WX_DEBUG_H_
+#define wxCOMPILE_TIME_ASSERT(expr, msg) \
+    struct wxMAKE_UNIQUE_ASSERT_NAME { unsigned int msg: expr; }
+
+/*
+   When using VC++ 6 with "Edit and Continue" on, the compiler completely
+   mishandles __LINE__ and so wxCOMPILE_TIME_ASSERT() doesn't work, provide a
+   way to make "unique" assert names by specifying a unique prefix explicitly
+ */
+#define wxMAKE_UNIQUE_ASSERT_NAME2(text) wxCONCAT(wxAssert_, text)
+
+#define wxCOMPILE_TIME_ASSERT2(expr, msg, text) \
+    struct wxMAKE_UNIQUE_ASSERT_NAME2(text) { unsigned int msg: expr; }
+
+/*  helpers for wxCOMPILE_TIME_ASSERT below, for private use only */
+#define wxMAKE_BITSIZE_MSG(type, size) type ## SmallerThan ## size ## Bits
+
+/*  a special case of compile time assert: check that the size of the given type */
+/*  is at least the given number of bits */
+#define wxASSERT_MIN_BITSIZE(type, size) \
+    wxCOMPILE_TIME_ASSERT(sizeof(type) * CHAR_BIT >= size, \
+                          wxMAKE_BITSIZE_MSG(type, size))
+
+/*  ---------------------------------------------------------------------------- */
+/*  other miscellaneous debugger-related functions */
+/*  ---------------------------------------------------------------------------- */
+
+/*  return true if we're running under debugger */
+/*  */
+/*  currently this only really works under Mac in CodeWarrior builds, it always */
+/*  returns false otherwise */
+#ifdef __cplusplus
+    #ifdef __WXMAC__
+        extern bool WXDLLIMPEXP_BASE wxIsDebuggerRunning();
+    #else /*  !Mac */
+        inline bool wxIsDebuggerRunning() { return false; }
+    #endif /*  Mac/!Mac */
+#endif /* __cplusplus */
+
+#endif  /*  _WX_DEBUG_H_ */