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1 /****************************************************************************
2  *
3  * config/public-macros.h
4  *
5  *   Define a set of compiler macros used in public FreeType headers.
6  *
7  * Copyright (C) 2020 by
8  * David Turner, Robert Wilhelm, and Werner Lemberg.
9  *
10  * This file is part of the FreeType project, and may only be used,
11  * modified, and distributed under the terms of the FreeType project
12  * license, LICENSE.TXT.  By continuing to use, modify, or distribute
13  * this file you indicate that you have read the license and
14  * understand and accept it fully.
15  *
16  */
17 
18   /*
19    * The definitions in this file are used by the public FreeType headers
20    * and thus should be considered part of the public API.
21    *
22    * Other compiler-specific macro definitions that are not exposed by the
23    * FreeType API should go into
24    * `include/freetype/internal/compiler-macros.h` instead.
25    */
26 #ifndef FREETYPE_CONFIG_PUBLIC_MACROS_H_
27 #define FREETYPE_CONFIG_PUBLIC_MACROS_H_
28 
29   /*
30    * `FT_BEGIN_HEADER` and `FT_END_HEADER` might have already been defined
31    * by `freetype/config/ftheader.h`, but we don't want to include this
32    * header here, so redefine the macros here only when needed.  Their
33    * definition is very stable, so keeping them in sync with the ones in the
34    * header should not be a maintenance issue.
35    */
36 #ifndef FT_BEGIN_HEADER
37 #ifdef __cplusplus
38 #define FT_BEGIN_HEADER  extern "C" {
39 #else
40 #define FT_BEGIN_HEADER  /* empty */
41 #endif
42 #endif  /* FT_BEGIN_HEADER */
43 
44 #ifndef FT_END_HEADER
45 #ifdef __cplusplus
46 #define FT_END_HEADER  }
47 #else
48 #define FT_END_HEADER  /* empty */
49 #endif
50 #endif  /* FT_END_HEADER */
51 
52 
53 FT_BEGIN_HEADER
54 
55   /*
56    * Mark a function declaration as public.  This ensures it will be
57    * properly exported to client code.  Place this before a function
58    * declaration.
59    *
60    * NOTE: This macro should be considered an internal implementation
61    * detail, and not part of the FreeType API.  It is only defined here
62    * because it is needed by `FT_EXPORT`.
63    */
64 
65   /* Visual C, mingw */
66 #if defined( _WIN32 )
67 
68 #if defined( FT2_BUILD_LIBRARY ) && defined( DLL_EXPORT )
69 #define FT_PUBLIC_FUNCTION_ATTRIBUTE  __declspec( dllexport )
70 #elif defined( DLL_IMPORT )
71 #define FT_PUBLIC_FUNCTION_ATTRIBUTE  __declspec( dllimport )
72 #endif
73 
74   /* gcc, clang */
75 #elif ( defined( __GNUC__ ) && __GNUC__ >= 4 ) || defined( __clang__ )
76 #define FT_PUBLIC_FUNCTION_ATTRIBUTE \
77           __attribute__(( visibility( "default" ) ))
78 
79   /* Sun */
80 #elif defined( __SUNPRO_C ) && __SUNPRO_C >= 0x550
81 #define FT_PUBLIC_FUNCTION_ATTRIBUTE  __global
82 #endif
83 
84 
85 #ifndef FT_PUBLIC_FUNCTION_ATTRIBUTE
86 #define FT_PUBLIC_FUNCTION_ATTRIBUTE  /* empty */
87 #endif
88 
89 
90   /*
91    * Define a public FreeType API function.  This ensures it is properly
92    * exported or imported at build time.  The macro parameter is the
93    * function's return type as in:
94    *
95    *   FT_EXPORT( FT_Bool )
96    *   FT_Object_Method( FT_Object  obj,
97    *                     ... );
98    *
99    * NOTE: This requires that all `FT_EXPORT` uses are inside
100    * `FT_BEGIN_HEADER ... FT_END_HEADER` blocks.  This guarantees that the
101    * functions are exported with C linkage, even when the header is included
102    * by a C++ source file.
103    */
104 #define FT_EXPORT( x )  FT_PUBLIC_FUNCTION_ATTRIBUTE extern x
105 
106   /*
107    * `FT_UNUSED` indicates that a given parameter is not used -- this is
108    * only used to get rid of unpleasant compiler warnings.
109    *
110    * Technically, this was not meant to be part of the public API, but some
111    * third-party code depends on it.
112    */
113 #ifndef FT_UNUSED
114 #define FT_UNUSED( arg )  ( (arg) = (arg) )
115 #endif
116 
117 
118 FT_END_HEADER
119 
120 #endif  /* FREETYPE_CONFIG_PUBLIC_MACROS_H_ */
121