SDL  2.0
SDL_error.h
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2021 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 /**
23  * \file SDL_error.h
24  *
25  * Simple error message routines for SDL.
26  */
27 
28 #ifndef SDL_error_h_
29 #define SDL_error_h_
30 
31 #include "SDL_stdinc.h"
32 
33 #include "begin_code.h"
34 /* Set up for C function definitions, even when using C++ */
35 #ifdef __cplusplus
36 extern "C" {
37 #endif
38 
39 /* Public functions */
40 
41 
42 /**
43  * Set the SDL error message for the current thread.
44  *
45  * Calling this function will replace any previous error message that was set.
46  *
47  * This function always returns -1, since SDL frequently uses -1 to signify an
48  * failing result, leading to this idiom:
49  *
50  * ```c
51  * if (error_code) {
52  * return SDL_SetError("This operation has failed: %d", error_code);
53  * }
54  * ```
55  *
56  * \param fmt a printf()-style message format string
57  * \param ... additional parameters matching % tokens in the `fmt` string, if
58  * any
59  * \returns always -1.
60  *
61  * \sa SDL_ClearError
62  * \sa SDL_GetError
63  */
64 extern DECLSPEC int SDLCALL SDL_SetError(SDL_PRINTF_FORMAT_STRING const char *fmt, ...) SDL_PRINTF_VARARG_FUNC(1);
65 
66 /**
67  * Retrieve a message about the last error that occurred on the current
68  * thread.
69  *
70  * It is possible for multiple errors to occur before calling SDL_GetError().
71  * Only the last error is returned.
72  *
73  * The message is only applicable when an SDL function has signaled an error.
74  * You must check the return values of SDL function calls to determine when to
75  * appropriately call SDL_GetError(). You should _not_ use the results of
76  * SDL_GetError() to decide if an error has occurred! Sometimes SDL will set
77  * an error string even when reporting success.
78  *
79  * SDL will _not_ clear the error string for successful API calls. You _must_
80  * check return values for failure cases before you can assume the error
81  * string applies.
82  *
83  * Error strings are set per-thread, so an error set in a different thread
84  * will not interfere with the current thread's operation.
85  *
86  * The returned string is internally allocated and must not be freed by the
87  * application.
88  *
89  * \returns a message with information about the specific error that occurred,
90  * or an empty string if there hasn't been an error message set since
91  * the last call to SDL_ClearError(). The message is only applicable
92  * when an SDL function has signaled an error. You must check the
93  * return values of SDL function calls to determine when to
94  * appropriately call SDL_GetError().
95  *
96  * \sa SDL_ClearError
97  * \sa SDL_SetError
98  */
99 extern DECLSPEC const char *SDLCALL SDL_GetError(void);
100 
101 /**
102  * Get the last error message that was set for the current thread.
103  *
104  * This allows the caller to copy the error string into a provided buffer, but
105  * otherwise operates exactly the same as SDL_GetError().
106  *
107  * \param errstr A buffer to fill with the last error message that was set for
108  * the current thread
109  * \param maxlen The size of the buffer pointed to by the errstr parameter
110  * \returns the pointer passed in as the `errstr` parameter.
111  *
112  * \sa SDL_GetError
113  */
114 extern DECLSPEC char * SDLCALL SDL_GetErrorMsg(char *errstr, int maxlen);
115 
116 /**
117  * Clear any previous error message for this thread.
118  *
119  * \sa SDL_GetError
120  * \sa SDL_SetError
121  */
122 extern DECLSPEC void SDLCALL SDL_ClearError(void);
123 
124 /**
125  * \name Internal error functions
126  *
127  * \internal
128  * Private error reporting function - used internally.
129  */
130 /* @{ */
131 #define SDL_OutOfMemory() SDL_Error(SDL_ENOMEM)
132 #define SDL_Unsupported() SDL_Error(SDL_UNSUPPORTED)
133 #define SDL_InvalidParamError(param) SDL_SetError("Parameter '%s' is invalid", (param))
134 typedef enum
135 {
142 } SDL_errorcode;
143 /* SDL_Error() unconditionally returns -1. */
144 extern DECLSPEC int SDLCALL SDL_Error(SDL_errorcode code);
145 /* @} *//* Internal error functions */
146 
147 /* Ends C function definitions when using C++ */
148 #ifdef __cplusplus
149 }
150 #endif
151 #include "close_code.h"
152 
153 #endif /* SDL_error_h_ */
154 
155 /* vi: set ts=4 sw=4 expandtab: */
SDL_errorcode
Definition: SDL_error.h:134
int SDL_SetError(SDL_PRINTF_FORMAT_STRING const char *fmt,...) SDL_PRINTF_VARARG_FUNC(1)
void SDL_ClearError(void)
const char * SDL_GetError(void)
char * SDL_GetErrorMsg(char *errstr, int maxlen)
#define SDL_PRINTF_FORMAT_STRING
Definition: SDL_stdinc.h:334
int SDL_Error(SDL_errorcode code)
#define SDL_PRINTF_VARARG_FUNC(fmtargnumber)
Definition: SDL_stdinc.h:341