Enchant: libgnu/relocatable.h Source File

Enchant Generic spell checking library

relocatable.h
1 /* Provide relocatable packages.
2 Copyright (C) 2003, 2005, 2008-2024 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2003.
4
5 This file is free software: you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
9
10 This file is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18 #ifndef _RELOCATABLE_H
19 #define _RELOCATABLE_H
20
21 /* This file uses _GL_ATTRIBUTE_MALLOC, HAVE_VISIBILITY. */
22 #if !_GL_CONFIG_H_INCLUDED
23 #error "Please include config.h first."
24 #endif
25
26 #include <stdlib.h>
27
28 #ifdef __cplusplus
29 extern "C" {
30 #endif
31
32
33 /* This can be enabled through the configure --enable-relocatable option. */
34 #if ENABLE_RELOCATABLE
35
36 /* When building a shared library, we must export some functions.
37 Note that because this is a private .h file, we don't need to use
38 __declspec(dllimport) in any case. */
39 #if HAVE_VISIBILITY && BUILDING_DLL
40 # define RELOCATABLE_SHLIB_EXPORTED __attribute__((__visibility__("default")))
41 #elif defined _MSC_VER && BUILDING_DLL
42 /* When building with MSVC, exporting a symbol means that the object file
43 contains a "linker directive" of the form /EXPORT:symbol. This can be
44 inspected through the "objdump -s --section=.drectve FILE" or
45 "dumpbin /directives FILE" commands.
46 The symbols from this file should be exported if and only if the object
47 file gets included in a DLL. Libtool, on Windows platforms, defines
48 the C macro DLL_EXPORT (together with PIC) when compiling for a shared
49 library (called DLL under Windows) and does not define it when compiling
50 an object file meant to be linked statically into some executable. */
51 # if defined DLL_EXPORT
52 # define RELOCATABLE_SHLIB_EXPORTED __declspec(dllexport)
53 # else
54 # define RELOCATABLE_SHLIB_EXPORTED
55 # endif
56 #else
57 # define RELOCATABLE_SHLIB_EXPORTED
58 #endif
59
60 /* Sets the original and the current installation prefix of the package.
61 Relocation simply replaces a pathname starting with the original prefix
62 by the corresponding pathname with the current prefix instead. Both
63 prefixes should be directory names without trailing slash (i.e. use ""
64 instead of "/"). */
65 extern RELOCATABLE_SHLIB_EXPORTED void
66 set_relocation_prefix (const char *orig_prefix,
67 const char *curr_prefix);
68
69 /* Returns the pathname, relocated according to the current installation
70 directory.
71 The returned string is either PATHNAME unmodified or a freshly allocated
72 string that you can free with free() after casting it to 'char *'. */
73 extern const char * relocate (const char *pathname);
74
75 /* Returns the pathname, relocated according to the current installation
76 directory.
77 This function sets *ALLOCATEDP to the allocated memory, or to NULL if
78 no memory allocation occurs. So that, after you're done with the return
79 value, to reclaim allocated memory, you can do: free (*ALLOCATEDP). */
80 extern const char * relocate2 (const char *pathname, char **allocatedp);
81
82 /* Memory management: relocate() potentially allocates memory, because it has
83 to construct a fresh pathname. If this is a problem because your program
84 calls relocate() frequently or because you want to fix all potential memory
85 leaks anyway, you have three options:
86 1) Use this idiom:
87 const char *pathname = ...;
88 const char *rel_pathname = relocate (pathname);
89 ...
90 if (rel_pathname != pathname)
91 free ((char *) rel_pathname);
92 2) Use this idiom:
93 char *allocated;
94 const char *rel_pathname = relocate2 (..., &allocated);
95 ...
96 free (allocated);
97 3) Think about caching the result. */
98
99 /* Convenience function:
100 Computes the current installation prefix, based on the original
101 installation prefix, the original installation directory of a particular
102 file, and the current pathname of this file.
103 Returns it, freshly allocated. Returns NULL upon failure. */
104 extern char * compute_curr_prefix (const char *orig_installprefix,
105 const char *orig_installdir,
106 const char *curr_pathname)
107 _GL_ATTRIBUTE_MALLOC _GL_ATTRIBUTE_DEALLOC_FREE;
108
109 #else
110
111 /* By default, we use the hardwired pathnames. */
112 #define set_relocation_prefix(orig_prefix, curr_prefix) \
113 ((void) (orig_prefix), (void) (curr_prefix))
114 #define relocate(pathname) (pathname)
115 #define relocate2(pathname,allocatedp) (*(allocatedp) = NULL, (pathname))
116
117 #endif
118
119
120 #ifdef __cplusplus
121 }
122 #endif
123
124 #endif /* _RELOCATABLE_H */