include/SDL_assert.h
author Sam Lantinga <slouken@libsdl.org>
Sat, 18 May 2013 14:17:52 -0700
changeset 7191 75360622e65f
parent 6885 700f1b25f77f
child 7664 6995a81e065a
permissions -rw-r--r--
File style cleanup for the SDL 2.0 release
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 
    22 #ifndef _SDL_assert_h
    23 #define _SDL_assert_h
    24 
    25 #include "SDL_config.h"
    26 
    27 #include "begin_code.h"
    28 /* Set up for C function definitions, even when using C++ */
    29 #ifdef __cplusplus
    30 extern "C" {
    31 #endif
    32 
    33 #ifndef SDL_ASSERT_LEVEL
    34 #ifdef SDL_DEFAULT_ASSERT_LEVEL
    35 #define SDL_ASSERT_LEVEL SDL_DEFAULT_ASSERT_LEVEL
    36 #elif defined(_DEBUG) || defined(DEBUG) || \
    37       (defined(__GNUC__) && !defined(__OPTIMIZE__))
    38 #define SDL_ASSERT_LEVEL 2
    39 #else
    40 #define SDL_ASSERT_LEVEL 1
    41 #endif
    42 #endif /* SDL_ASSERT_LEVEL */
    43 
    44 /*
    45 These are macros and not first class functions so that the debugger breaks
    46 on the assertion line and not in some random guts of SDL, and so each
    47 assert can have unique static variables associated with it.
    48 */
    49 
    50 #if defined(_MSC_VER)
    51 /* Don't include intrin.h here because it contains C++ code */
    52     extern void __cdecl __debugbreak(void);
    53     #define SDL_TriggerBreakpoint() __debugbreak()
    54 #elif (defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)))
    55     #define SDL_TriggerBreakpoint() __asm__ __volatile__ ( "int $3\n\t" )
    56 #elif defined(HAVE_SIGNAL_H)
    57     #include <signal.h>
    58     #define SDL_TriggerBreakpoint() raise(SIGTRAP)
    59 #else
    60     /* How do we trigger breakpoints on this platform? */
    61     #define SDL_TriggerBreakpoint()
    62 #endif
    63 
    64 #if defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 supports __func__ as a standard. */
    65 #   define SDL_FUNCTION __func__
    66 #elif ((__GNUC__ >= 2) || defined(_MSC_VER))
    67 #   define SDL_FUNCTION __FUNCTION__
    68 #else
    69 #   define SDL_FUNCTION "???"
    70 #endif
    71 #define SDL_FILE    __FILE__
    72 #define SDL_LINE    __LINE__
    73 
    74 /*
    75 sizeof (x) makes the compiler still parse the expression even without
    76 assertions enabled, so the code is always checked at compile time, but
    77 doesn't actually generate code for it, so there are no side effects or
    78 expensive checks at run time, just the constant size of what x WOULD be,
    79 which presumably gets optimized out as unused.
    80 This also solves the problem of...
    81 
    82     int somevalue = blah();
    83     SDL_assert(somevalue == 1);
    84 
    85 ...which would cause compiles to complain that somevalue is unused if we
    86 disable assertions.
    87 */
    88 
    89 #define SDL_disabled_assert(condition) \
    90     do { (void) sizeof ((condition)); } while (0)
    91 
    92 typedef enum
    93 {
    94     SDL_ASSERTION_RETRY,  /**< Retry the assert immediately. */
    95     SDL_ASSERTION_BREAK,  /**< Make the debugger trigger a breakpoint. */
    96     SDL_ASSERTION_ABORT,  /**< Terminate the program. */
    97     SDL_ASSERTION_IGNORE,  /**< Ignore the assert. */
    98     SDL_ASSERTION_ALWAYS_IGNORE  /**< Ignore the assert from now on. */
    99 } SDL_assert_state;
   100 
   101 typedef struct SDL_assert_data
   102 {
   103     int always_ignore;
   104     unsigned int trigger_count;
   105     const char *condition;
   106     const char *filename;
   107     int linenum;
   108     const char *function;
   109     const struct SDL_assert_data *next;
   110 } SDL_assert_data;
   111 
   112 #if (SDL_ASSERT_LEVEL > 0)
   113 
   114 /* Never call this directly. Use the SDL_assert* macros. */
   115 extern DECLSPEC SDL_assert_state SDLCALL SDL_ReportAssertion(SDL_assert_data *,
   116                                                              const char *,
   117                                                              const char *, int);
   118 
   119 /* the do {} while(0) avoids dangling else problems:
   120     if (x) SDL_assert(y); else blah();
   121        ... without the do/while, the "else" could attach to this macro's "if".
   122    We try to handle just the minimum we need here in a macro...the loop,
   123    the static vars, and break points. The heavy lifting is handled in
   124    SDL_ReportAssertion(), in SDL_assert.c.
   125 */
   126 #define SDL_enabled_assert(condition) \
   127     do { \
   128         while ( !(condition) ) { \
   129             static struct SDL_assert_data assert_data = { \
   130                 0, 0, #condition, 0, 0, 0, 0 \
   131             }; \
   132             const SDL_assert_state state = SDL_ReportAssertion(&assert_data, \
   133                                                                SDL_FUNCTION, \
   134                                                                SDL_FILE, \
   135                                                                SDL_LINE); \
   136             if (state == SDL_ASSERTION_RETRY) { \
   137                 continue; /* go again. */ \
   138             } else if (state == SDL_ASSERTION_BREAK) { \
   139                 SDL_TriggerBreakpoint(); \
   140             } \
   141             break; /* not retrying. */ \
   142         } \
   143     } while (0)
   144 
   145 #endif  /* enabled assertions support code */
   146 
   147 /* Enable various levels of assertions. */
   148 #if SDL_ASSERT_LEVEL == 0   /* assertions disabled */
   149 #   define SDL_assert(condition) SDL_disabled_assert(condition)
   150 #   define SDL_assert_release(condition) SDL_disabled_assert(condition)
   151 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
   152 #elif SDL_ASSERT_LEVEL == 1  /* release settings. */
   153 #   define SDL_assert(condition) SDL_disabled_assert(condition)
   154 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
   155 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
   156 #elif SDL_ASSERT_LEVEL == 2  /* normal settings. */
   157 #   define SDL_assert(condition) SDL_enabled_assert(condition)
   158 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
   159 #   define SDL_assert_paranoid(condition) SDL_disabled_assert(condition)
   160 #elif SDL_ASSERT_LEVEL == 3  /* paranoid settings. */
   161 #   define SDL_assert(condition) SDL_enabled_assert(condition)
   162 #   define SDL_assert_release(condition) SDL_enabled_assert(condition)
   163 #   define SDL_assert_paranoid(condition) SDL_enabled_assert(condition)
   164 #else
   165 #   error Unknown assertion level.
   166 #endif
   167 
   168 
   169 typedef SDL_assert_state (SDLCALL *SDL_AssertionHandler)(
   170                                  const SDL_assert_data* data, void* userdata);
   171 
   172 /**
   173  *  \brief Set an application-defined assertion handler.
   174  *
   175  *  This allows an app to show its own assertion UI and/or force the
   176  *  response to an assertion failure. If the app doesn't provide this, SDL
   177  *  will try to do the right thing, popping up a system-specific GUI dialog,
   178  *  and probably minimizing any fullscreen windows.
   179  *
   180  *  This callback may fire from any thread, but it runs wrapped in a mutex, so
   181  *  it will only fire from one thread at a time.
   182  *
   183  *  Setting the callback to NULL restores SDL's original internal handler.
   184  *
   185  *  This callback is NOT reset to SDL's internal handler upon SDL_Quit()!
   186  *
   187  *  \return SDL_assert_state value of how to handle the assertion failure.
   188  *
   189  *  \param handler Callback function, called when an assertion fails.
   190  *  \param userdata A pointer passed to the callback as-is.
   191  */
   192 extern DECLSPEC void SDLCALL SDL_SetAssertionHandler(
   193                                             SDL_AssertionHandler handler,
   194                                             void *userdata);
   195 
   196 /**
   197  *  \brief Get a list of all assertion failures.
   198  *
   199  *  Get all assertions triggered since last call to SDL_ResetAssertionReport(),
   200  *  or the start of the program.
   201  *
   202  *  The proper way to examine this data looks something like this:
   203  *
   204  *  <code>
   205  *  const SDL_assert_data *item = SDL_GetAssertionReport();
   206  *  while (item) {
   207  *      printf("'%s', %s (%s:%d), triggered %u times, always ignore: %s.\n",
   208  *             item->condition, item->function, item->filename,
   209  *             item->linenum, item->trigger_count,
   210  *             item->always_ignore ? "yes" : "no");
   211  *      item = item->next;
   212  *  }
   213  *  </code>
   214  *
   215  *  \return List of all assertions.
   216  *  \sa SDL_ResetAssertionReport
   217  */
   218 extern DECLSPEC const SDL_assert_data * SDLCALL SDL_GetAssertionReport(void);
   219 
   220 /**
   221  *  \brief Reset the list of all assertion failures.
   222  *
   223  *  Reset list of all assertions triggered.
   224  *
   225  *  \sa SDL_GetAssertionReport
   226  */
   227 extern DECLSPEC void SDLCALL SDL_ResetAssertionReport(void);
   228 
   229 /* Ends C function definitions when using C++ */
   230 #ifdef __cplusplus
   231 }
   232 #endif
   233 #include "close_code.h"
   234 
   235 #endif /* _SDL_assert_h */
   236 
   237 /* vi: set ts=4 sw=4 expandtab: */