include/SDL_error.h

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

/**
 *  \file SDL_error.h
 *
 *  Simple error message routines for SDL.
 */

#ifndef SDL_error_h_
#define SDL_error_h_

#include "SDL_stdinc.h"

#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif

/* Public functions */


/**
 * Set the SDL error message for the current thread.
 *
 * Calling this function will replace any previous error message that was set.
 *
 * This function always returns -1, since SDL frequently uses -1 to signify an
 * failing result, leading to this idiom:
 *
 * ```c
 * if (error_code) {
 *     return SDL_SetError("This operation has failed: %d", error_code);
 * }
 * ```
 *
 * \param fmt a printf()-style message format string
 * \param ... additional parameters matching % tokens in the `fmt` string, if
 *            any
 * \returns always -1.
 *
 * \sa SDL_ClearError
 * \sa SDL_GetError
 */
extern DECLSPEC int SDLCALL SDL_SetError(SDL_PRINTF_FORMAT_STRING const char *fmt, ...) SDL_PRINTF_VARARG_FUNC(1);

/**
 * Retrieve a message about the last error that occurred on the current
 * thread.
 *
 * It is possible for multiple errors to occur before calling SDL_GetError().
 * Only the last error is returned.
 *
 * The message is only applicable when an SDL function has signaled an error.
 * You must check the return values of SDL function calls to determine when to
 * appropriately call SDL_GetError(). You should _not_ use the results of
 * SDL_GetError() to decide if an error has occurred! Sometimes SDL will set
 * an error string even when reporting success.
 *
 * SDL will _not_ clear the error string for successful API calls. You _must_
 * check return values for failure cases before you can assume the error
 * string applies.
 *
 * Error strings are set per-thread, so an error set in a different thread
 * will not interfere with the current thread's operation.
 *
 * The returned string is internally allocated and must not be freed by the
 * application.
 *
 * \returns a message with information about the specific error that occurred,
 *          or an empty string if there hasn't been an error message set since
 *          the last call to SDL_ClearError(). The message is only applicable
 *          when an SDL function has signaled an error. You must check the
 *          return values of SDL function calls to determine when to
 *          appropriately call SDL_GetError().
 *
 * \sa SDL_ClearError
 * \sa SDL_SetError
 */
extern DECLSPEC const char *SDLCALL SDL_GetError(void);

/**
 * Get the last error message that was set for the current thread.
 *
 * This allows the caller to copy the error string into a provided buffer, but
 * otherwise operates exactly the same as SDL_GetError().
 *
 * \param errstr A buffer to fill with the last error message that was set for
 *               the current thread
 * \param maxlen The size of the buffer pointed to by the errstr parameter
 * \returns the pointer passed in as the `errstr` parameter.
 *
 * \sa SDL_GetError
 */
extern DECLSPEC char * SDLCALL SDL_GetErrorMsg(char *errstr, int maxlen);

/**
 * Clear any previous error message for this thread.
 *
 * \sa SDL_GetError
 * \sa SDL_SetError
 */
extern DECLSPEC void SDLCALL SDL_ClearError(void);

/**
 *  \name Internal error functions
 *
 *  \internal
 *  Private error reporting function - used internally.
 */
/* @{ */
#define SDL_OutOfMemory()   SDL_Error(SDL_ENOMEM)
#define SDL_Unsupported()   SDL_Error(SDL_UNSUPPORTED)
#define SDL_InvalidParamError(param)    SDL_SetError("Parameter '%s' is invalid", (param))
typedef enum
{
    SDL_ENOMEM,
    SDL_EFREAD,
    SDL_EFWRITE,
    SDL_EFSEEK,
    SDL_UNSUPPORTED,
    SDL_LASTERROR
} SDL_errorcode;
/* SDL_Error() unconditionally returns -1. */
extern DECLSPEC int SDLCALL SDL_Error(SDL_errorcode code);
/* @} *//* Internal error functions */

/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include "close_code.h"

#endif /* SDL_error_h_ */

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