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Edit File: fterrors.h
/**************************************************************************** * * fterrors.h * * FreeType error code handling (specification). * * Copyright (C) 1996-2020 by * David Turner, Robert Wilhelm, and Werner Lemberg. * * This file is part of the FreeType project, and may only be used, * modified, and distributed under the terms of the FreeType project * license, LICENSE.TXT. By continuing to use, modify, or distribute * this file you indicate that you have read the license and * understand and accept it fully. * */ /************************************************************************** * * @section: * error_enumerations * * @title: * Error Enumerations * * @abstract: * How to handle errors and error strings. * * @description: * The header file `fterrors.h` (which is automatically included by * `freetype.h` defines the handling of FreeType's enumeration * constants. It can also be used to generate error message strings * with a small macro trick explained below. * * **Error Formats** * * The configuration macro `FT_CONFIG_OPTION_USE_MODULE_ERRORS` can be * defined in `ftoption.h` in order to make the higher byte indicate the * module where the error has happened (this is not compatible with * standard builds of FreeType~2, however). See the file `ftmoderr.h` * for more details. * * **Error Message Strings** * * Error definitions are set up with special macros that allow client * applications to build a table of error message strings. The strings * are not included in a normal build of FreeType~2 to save space (most * client applications do not use them). * * To do so, you have to define the following macros before including * this file. * * ``` * FT_ERROR_START_LIST * ``` * * This macro is called before anything else to define the start of the * error list. It is followed by several `FT_ERROR_DEF` calls. * * ``` * FT_ERROR_DEF( e, v, s ) * ``` * * This macro is called to define one single error. 'e' is the error * code identifier (e.g., `Invalid_Argument`), 'v' is the error's * numerical value, and 's' is the corresponding error string. * * ``` * FT_ERROR_END_LIST * ``` * * This macro ends the list. * * Additionally, you have to undefine `FTERRORS_H_` before #including * this file. * * Here is a simple example. * * ``` * #undef FTERRORS_H_ * #define FT_ERRORDEF( e, v, s ) { e, s }, * #define FT_ERROR_START_LIST { * #define FT_ERROR_END_LIST { 0, NULL } }; * * const struct * { * int err_code; * const char* err_msg; * } ft_errors[] = * * #include <freetype/fterrors.h> * ``` * * An alternative to using an array is a switch statement. * * ``` * #undef FTERRORS_H_ * #define FT_ERROR_START_LIST switch ( error_code ) { * #define FT_ERRORDEF( e, v, s ) case v: return s; * #define FT_ERROR_END_LIST } * ``` * * If you use `FT_CONFIG_OPTION_USE_MODULE_ERRORS`, `error_code` should * be replaced with `FT_ERROR_BASE(error_code)` in the last example. */ /* */ /* In previous FreeType versions we used `__FTERRORS_H__`. However, */ /* using two successive underscores in a non-system symbol name */ /* violates the C (and C++) standard, so it was changed to the */ /* current form. In spite of this, we have to make */ /* */ /* ``` */ /* #undefine __FTERRORS_H__ */ /* ``` */ /* */ /* work for backward compatibility. */ /* */ #if !( defined( FTERRORS_H_ ) && defined ( __FTERRORS_H__ ) ) #define FTERRORS_H_ #define __FTERRORS_H__ /* include module base error codes */ #include <freetype/ftmoderr.h> /*******************************************************************/ /*******************************************************************/ /***** *****/ /***** SETUP MACROS *****/ /***** *****/ /*******************************************************************/ /*******************************************************************/ #undef FT_NEED_EXTERN_C /* FT_ERR_PREFIX is used as a prefix for error identifiers. */ /* By default, we use `FT_Err_`. */ /* */ #ifndef FT_ERR_PREFIX #define FT_ERR_PREFIX FT_Err_ #endif /* FT_ERR_BASE is used as the base for module-specific errors. */ /* */ #ifdef FT_CONFIG_OPTION_USE_MODULE_ERRORS #ifndef FT_ERR_BASE #define FT_ERR_BASE FT_Mod_Err_Base #endif #else #undef FT_ERR_BASE #define FT_ERR_BASE 0 #endif /* FT_CONFIG_OPTION_USE_MODULE_ERRORS */ /* If FT_ERRORDEF is not defined, we need to define a simple */ /* enumeration type. */ /* */ #ifndef FT_ERRORDEF #define FT_INCLUDE_ERR_PROTOS #define FT_ERRORDEF( e, v, s ) e = v, #define FT_ERROR_START_LIST enum { #define FT_ERROR_END_LIST FT_ERR_CAT( FT_ERR_PREFIX, Max ) }; #ifdef __cplusplus #define FT_NEED_EXTERN_C extern "C" { #endif #endif /* !FT_ERRORDEF */ /* this macro is used to define an error */ #define FT_ERRORDEF_( e, v, s ) \ FT_ERRORDEF( FT_ERR_CAT( FT_ERR_PREFIX, e ), v + FT_ERR_BASE, s ) /* this is only used for <module>_Err_Ok, which must be 0! */ #define FT_NOERRORDEF_( e, v, s ) \ FT_ERRORDEF( FT_ERR_CAT( FT_ERR_PREFIX, e ), v, s ) #ifdef FT_ERROR_START_LIST FT_ERROR_START_LIST #endif /* now include the error codes */ #include <freetype/fterrdef.h> #ifdef FT_ERROR_END_LIST FT_ERROR_END_LIST #endif /*******************************************************************/ /*******************************************************************/ /***** *****/ /***** SIMPLE CLEANUP *****/ /***** *****/ /*******************************************************************/ /*******************************************************************/ #ifdef FT_NEED_EXTERN_C } #endif #undef FT_ERROR_START_LIST #undef FT_ERROR_END_LIST #undef FT_ERRORDEF #undef FT_ERRORDEF_ #undef FT_NOERRORDEF_ #undef FT_NEED_EXTERN_C #undef FT_ERR_BASE /* FT_ERR_PREFIX is needed internally */ #ifndef FT2_BUILD_LIBRARY #undef FT_ERR_PREFIX #endif /* FT_INCLUDE_ERR_PROTOS: Control whether function prototypes should be */ /* included with */ /* */ /* #include <freetype/fterrors.h> */ /* */ /* This is only true where `FT_ERRORDEF` is */ /* undefined. */ /* */ /* FT_ERR_PROTOS_DEFINED: Actual multiple-inclusion protection of */ /* `fterrors.h`. */ #ifdef FT_INCLUDE_ERR_PROTOS #undef FT_INCLUDE_ERR_PROTOS #ifndef FT_ERR_PROTOS_DEFINED #define FT_ERR_PROTOS_DEFINED FT_BEGIN_HEADER /************************************************************************** * * @function: * FT_Error_String * * @description: * Retrieve the description of a valid FreeType error code. * * @input: * error_code :: * A valid FreeType error code. * * @return: * A C~string or `NULL`, if any error occurred. * * @note: * FreeType has to be compiled with `FT_CONFIG_OPTION_ERROR_STRINGS` or * `FT_DEBUG_LEVEL_ERROR` to get meaningful descriptions. * 'error_string' will be `NULL` otherwise. * * Module identification will be ignored: * * ```c * strcmp( FT_Error_String( FT_Err_Unknown_File_Format ), * FT_Error_String( BDF_Err_Unknown_File_Format ) ) == 0; * ``` */ FT_EXPORT( const char* ) FT_Error_String( FT_Error error_code ); FT_END_HEADER #endif /* FT_ERR_PROTOS_DEFINED */ #endif /* FT_INCLUDE_ERR_PROTOS */ #endif /* !(FTERRORS_H_ && __FTERRORS_H__) */ /* END */