README
1 dlcompat for Darwin
2 =========================
3
4 This is dlcompat, a small library that emulates the dlopen()
5 interface on top of Darwin's dyld API.
6
7 dlcompat allows loading a ".dylib" library (as long as the RTLD_LOCAL
8 flag isn't passed to dlopen()). It can be configured to yield a warning
9 when trying to close it (dynamic libraries cannot currently be unloaded).
10
11 It automatically searches for modules in several directories when no
12 absolute path is specified and the module is not found in the current
13 directory.
14
15 The paths searched are those specified in the environment variables
16 LD_LIBRARY_PATH and DYLD_LIBRARY_PATH plus /lib, /usr/local/lib and
17 /usr/lib or the path specified in the environment variable
18 DYLD_FALLBACK_LIBRARY_PATH.
19
20 In the default install the behavior of dlsym is to automatically prepend
21 an underscore to passed in symbol names, this allows easier porting of
22 applications which were written specifically for ELF based lifeforms.
23
24 Installation
25 --------------
26 Type:
27 ./configure
28 make
29 sudo make install
30
31 This will compile the source file, generate both a static and shared
32 library called libdl and install it into /usr/local/lib. The header
33 file dlfcn.h will be installed in /usr/local/include.
34
35 If you want to place the files somewhere else, run
36
37 make clean
38 ./configure --prefix=<prefix>
39 make
40 sudo make install
41
42 where <prefix> is the hierarchy you want to install into, e.g. /usr
43 for /usr/lib and /usr/include (_NOT_ recommended!).
44
45 To enable debugging output (useful for me), run
46
47 make clean
48 ./configure --enable-debug
49 make
50 sudo make install
51
52 If you want old dlcompat style behavior of not prepending the underscore
53 on calls to dlsym then type:
54
55 make clean
56 ./configure --enable-fink
57 make
58 sudo make install
59
60 Usage
61 -------
62 Software that uses GNU autoconf will likely check for a library called
63 libdl, that's why I named it that way. For software that doesn't find
64 the library on its own, you must add a '-ldl' to the appropriate
65 Makefile (or environment) variable, usually LIBS.
66
67 If you installed dlcompat into a directory other than /usr/local/lib,
68 you must tell the compiler where to find it. Add '-L<prefix>/lib' to
69 LDFLAGS (or CFLAGS) and '-I<prefix>/include' to CPPFLAGS (or CFLAGS).
70
71 Notes
72 -----
73 If you are writing new software and plan to have Mac OX X compatibility you
74 should look at the dyld api's in /usr/include/mach-o/dyld.h, rather than
75 using dlcompat, using the native api's is the supported method of loading
76 dynamically on Mac OS X, if you want an small example, look at dlfcn_simple.c,
77 which should help get you started.
78
79 Also note that the functions in dlcompat are not thread safe, and while it is not
80 POSIX spec compliant, it is about as close to compliance as it is going to get though.
81
82 You can always get the latest version from opendarwin cvs:
83
84 cvs -d :pserver:anonymous (a] anoncvs.opendarwin.org:/cvs/od login
85 cvs -z3 -d :pserver:anonymous (a] anoncvs.opendarwin.org:/cvs/od \
86 co -d dlcompat proj/dlcompat
87
88
89 It is hoped that this library will be useful, and as bug free as possible, if you find
90 any bugs please let us know about them so they can be fixed.
91
92 Please send bug reports to Peter O'Gorman <ogorman (a] users.sourceforge.net>
93
94 Thanks.
95
96
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