include/SDL_assert.h
author Sam Lantinga <slouken@libsdl.org>
Mon, 17 Jan 2011 09:09:15 -0800
changeset 5009 b21ad135d86b
parent 3697 f7b03b6838cb
child 5011 d306007299ac
permissions -rw-r--r--
Minor documentation consistency cleanup
     1 /*
     2     SDL - Simple DirectMedia Layer
     3     Copyright (C) 1997-2010 Sam Lantinga
     4 
     5     This library is free software; you can redistribute it and/or
     6     modify it under the terms of the GNU Lesser General Public
     7     License as published by the Free Software Foundation; either
     8     version 2.1 of the License, or (at your option) any later version.
     9 
    10     This library is distributed in the hope that it will be useful,
    11     but WITHOUT ANY WARRANTY; without even the implied warranty of
    12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    13     Lesser General Public License for more details.
    14 
    15     You should have received a copy of the GNU Lesser General Public
    16     License along with this library; if not, write to the Free Software
    17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
    18 
    19     Sam Lantinga
    20     slouken@libsdl.org
    21 */
    22 
    23 #ifndef _SDL_assert_h
    24 #define _SDL_assert_h
    25 
    26 #include "SDL_config.h"
    27 
    28 #include "begin_code.h"
    29 /* Set up for C function definitions, even when using C++ */
    30 #ifdef __cplusplus
    31 /* *INDENT-OFF* */
    32 extern "C" {
    33 /* *INDENT-ON* */
    34 #endif
    35 
    36 #ifndef SDL_ASSERT_LEVEL
    37 #ifdef SDL_DEFAULT_ASSERT_LEVEL
    38 #define SDL_ASSERT_LEVEL SDL_DEFAULT_ASSERT_LEVEL
    39 #elif defined(_DEBUG) || defined(DEBUG) || \
    40       (defined(__GNUC__) && !defined(__OPTIMIZE__))
    41 #define SDL_ASSERT_LEVEL 2
    42 #else
    43 #define SDL_ASSERT_LEVEL 1
    44 #endif
    45 #endif /* SDL_ASSERT_LEVEL */
    46 
    47 /*
    48 These are macros and not first class functions so that the debugger breaks
    49 on the assertion line and not in some random guts of SDL, and so each
    50 assert can have unique static variables associated with it.
    51 */
    52 
    53 #if (defined(_MSC_VER) && ((_M_IX86) || (_M_X64)))
    54     #define SDL_TriggerBreakpoint() __asm { int 3 }
    55 #elif (defined(__GNUC__) && ((__i386__) || (__x86_64__)))
    56     #define SDL_TriggerBreakpoint() __asm__ __volatile__ ( "int $3\n\t" )
    57 #elif defined(HAVE_SIGNAL_H)
    58     #include <signal.h>
    59     #define SDL_TriggerBreakpoint() raise(SIGTRAP)
    60 #else
    61     /* How do we trigger breakpoints on this platform? */
    62     #define SDL_TriggerBreakpoint()
    63 #endif
    64 
    65 #if (__STDC_VERSION__ >= 199901L) /* C99 supports __func__ as a standard. */
    66 #   define SDL_FUNCTION __func__
    67 #elif ((__GNUC__ >= 2) || defined(_MSC_VER))
    68 #   define SDL_FUNCTION __FUNCTION__
    69 #else
    70 #   define SDL_FUNCTION "???"
    71 #endif
    72 #define SDL_FILE    __FILE__
    73 #define SDL_LINE    __LINE__
    74 
    75 /*
    76 sizeof (x) makes the compiler still parse the expression even without
    77 assertions enabled, so the code is always checked at compile time, but
    78 doesn't actually generate code for it, so there are no side effects or
    79 expensive checks at run time, just the constant size of what x WOULD be,
    80 which presumably gets optimized out as unused.
    81 This also solves the problem of...
    82 
    83     int somevalue = blah();
    84     SDL_assert(somevalue == 1);
    85 
    86 ...which would cause compiles to complain that somevalue is unused if we
    87 disable assertions.
    88 */
    89 
    90 #define SDL_disabled_assert(condition) \
    91     do { (void) sizeof ((condition)); } while (0)
    92 
    93 #if (SDL_ASSERT_LEVEL > 0)
    94 
    95 typedef enum
    96 {
    97     SDL_ASSERTION_RETRY,  /**< Retry the assert immediately. */
    98     SDL_ASSERTION_BREAK,  /**< Make the debugger trigger a breakpoint. */
    99     SDL_ASSERTION_ABORT,  /**< Terminate the program. */
   100     SDL_ASSERTION_IGNORE,  /**< Ignore the assert. */
   101     SDL_ASSERTION_ALWAYS_IGNORE,  /**< Ignore the assert from now on. */
   102 } SDL_assert_state;
   103 
   104 typedef struct SDL_assert_data
   105 {
   106     int always_ignore;
   107     unsigned int trigger_count;
   108     const char *condition;
   109     const char *filename;
   110     int linenum;
   111     const char *function;
   112     const struct SDL_assert_data *next;
   113 } SDL_assert_data;
   114 
   115 /* Never call this directly. Use the SDL_assert* macros. */
   116 extern DECLSPEC SDL_assert_state SDLCALL SDL_ReportAssertion(SDL_assert_data *,
   117                                                              const char *,
   118                                                              const char *, int);
   119 
   120 /* the do {} while(0) avoids dangling else problems:
   121     if (x) SDL_assert(y); else blah();
   122        ... without the do/while, the "else" could attach to this macro's "if".
   123    We try to handle just the minimum we need here in a macro...the loop,
   124    the static vars, and break points. The heavy lifting is handled in
   125    SDL_ReportAssertion(), in SDL_assert.c.
   126 */
   127 #define SDL_enabled_assert(condition) \
   128     do { \
   129         while ( !(condition) ) { \
   130             static struct SDL_assert_data assert_data = { \
   131                 0, 0, #condition, 0, 0, 0, 0 \
   132             }; \
   133             const SDL_assert_state state = SDL_ReportAssertion(&assert_data, \
   134                                                                SDL_FUNCTION, \
   135                                                                SDL_FILE, \
   136                                                                SDL_LINE); \
   137             if (state == SDL_ASSERTION_RETRY) { \
   138                 continue; /* go again. */ \
   139             } else if (state == SDL_ASSERTION_BREAK) { \
   140                 SDL_TriggerBreakpoint(); \
   141             } \
   142             break; /* not retrying. */ \
   143         } \
   144     } while (0)
   145 
   146 #endif  /* enabled assertions support code */
   147 
   148 /* Enable various levels of assertions. */
   149 #if SDL_ASSERT_LEVEL == 0   /* assertions disabled */
   150 #   define SDL_assert(condition) SDL_disabled_assert(condition)
   151 #   define SDL_assert_release(condition) SDL_disabled_assert(condition)
   152 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
   153 #elif SDL_ASSERT_LEVEL == 1  /* release settings. */
   154 #   define SDL_assert(condition) SDL_disabled_assert(condition)
   155 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
   156 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
   157 #elif SDL_ASSERT_LEVEL == 2  /* normal settings. */
   158 #   define SDL_assert(condition) SDL_enabled_assert(condition)
   159 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
   160 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
   161 #elif SDL_ASSERT_LEVEL == 3  /* paranoid settings. */
   162 #   define SDL_assert(condition) SDL_enabled_assert(condition)
   163 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
   164 #   define SDL_assert_paranoid(condition) SDL_enabled_assert(condition)
   165 #else
   166 #   error Unknown assertion level.
   167 #endif
   168 
   169 
   170 typedef SDL_assert_state (SDLCALL *SDL_AssertionHandler)(
   171                                     const SDL_assert_data *, void *userdata);
   172 
   173 /**
   174  *  \brief Set an application-defined assertion handler.
   175  *
   176  *  This allows an app to show its own assertion UI and/or force the
   177  *  response to an assertion failure. If the app doesn't provide this, SDL
   178  *  will try to do the right thing, popping up a system-specific GUI dialog,
   179  *  and probably minimizing any fullscreen windows.
   180  *
   181  *  This callback may fire from any thread, but it runs wrapped in a mutex, so
   182  *  it will only fire from one thread at a time.
   183  *
   184  *  Setting the callback to NULL restores SDL's original internal handler.
   185  *
   186  *  This callback is NOT reset to SDL's internal handler upon SDL_Quit()!
   187  *
   188  *  \return SDL_assert_state value of how to handle the assertion failure.
   189  *  
   190  *  \param handler Callback function, called when an assertion fails.
   191  *  \param userdata A pointer passed to the callback as-is.
   192  */
   193 extern DECLSPEC void SDLCALL SDL_SetAssertionHandler(
   194                                             SDL_AssertionHandler handler,
   195                                             void *userdata);
   196 
   197 /**
   198  *  \brief Get a list of all assertion failures.
   199  *
   200  *  Get all assertions triggered since last call to SDL_ResetAssertionReport(),
   201  *  or the start of the program.
   202  *
   203  *  The proper way to examine this data looks something like this:
   204  *
   205  *  <code>
   206  *  const SDL_assert_data *item = SDL_GetAssertionReport();
   207  *  while (item->condition) {
   208  *      printf("'%s', %s (%s:%d), triggered %u times, always ignore: %s.\n",
   209  *             item->condition, item->function, item->filename,
   210  *             item->linenum, item->trigger_count,
   211  *             item->always_ignore ? "yes" : "no");
   212  *      item = item->next;
   213  *  }
   214  *  </code>
   215  *
   216  *  \return List of all assertions. This never returns NULL,
   217  *          even if there are no items.
   218  *  \sa SDL_ResetAssertionReport
   219  */
   220 extern DECLSPEC const SDL_assert_data * SDLCALL SDL_GetAssertionReport(void);
   221 
   222 /**
   223  *  \brief Reset the list of all assertion failures.
   224  *
   225  *  Reset list of all assertions triggered.
   226  *
   227  *  \sa SDL_GetAssertionReport
   228  */
   229 extern DECLSPEC void SDLCALL SDL_ResetAssertionReport(void);
   230 
   231 /* Ends C function definitions when using C++ */
   232 #ifdef __cplusplus
   233 /* *INDENT-OFF* */
   234 }
   235 /* *INDENT-ON* */
   236 #endif
   237 #include "close_code.h"
   238 
   239 #endif /* _SDL_assert_h */
   240 
   241 /* vi: set ts=4 sw=4 expandtab: */