dlcompat for Darwin
=========================
This is dlcompat, a small library that emulates the dlopen()
interface on top of Darwin's dyld API.
dlcompat allows loading a ".dylib" library (as long as the RTLD_LOCAL
flag is NOT passed to dlopen()). It can be configured to yield a warning
when trying to close it (dynamic libraries cannot currently be unloaded).
It automatically searches for modules in several directories when no
absolute path is specified and the module is not found in the current
directory.
The paths searched are those specified in the environment variables
LD_LIBRARY_PATH and DYLD_LIBRARY_PATH plus /lib, /usr/local/lib and
/usr/lib or the path specified in the environment variable
DYLD_FALLBACK_LIBRARY_PATH.
In the default install the behavior of dlsym is to automatically prepend
an underscore to passed in symbol names, this allows easier porting of
applications which were written specifically for ELF based lifeforms.
Installation
--------------
Type:
./configure
make
sudo make install
This will compile the source file, generate both a static and shared
library called libdl and install it into /usr/local/lib. The header
file dlfcn.h will be installed in /usr/local/include, and the man pages
go in /usr/local/man.
If you want to place the files somewhere else, run
make clean
./configure --prefix=<prefix>
make
sudo make install
where <prefix> is the hierarchy you want to install into, e.g. /usr
for /usr/lib and /usr/include (_NOT_ recommended!).
To enable debugging output (useful for me), run
make clean
./configure --enable-debug
make
sudo make install
If you want old dlcompat style behavior of not prepending the underscore
on calls to dlsym then type:
make clean
./configure --enable-fink
make
sudo make install
Usage
-------
Software that uses GNU autoconf will likely check for a library called
libdl, that is why I named it that way. For software that does NOT find
the library on its own, you must add a '-ldl' to the appropriate
Makefile (or environment) variable, usually LIBS.
If you installed dlcompat into a directory other than /usr/local/lib,
you must tell the compiler where to find it. Add '-L<prefix>/lib' to
LDFLAGS (or CFLAGS) and '-I<prefix>/include' to CPPFLAGS (or CFLAGS).
Notes
-----
If you are writing new software and plan to have Mac OX X compatibility you
should look at the dyld api's in /usr/include/mach-o/dyld.h, rather than
using dlcompat, using the native api's is the supported method of loading
dynamically on Mac OS X, if you want an small example, look at
dlfcn_simple.c, which should help get you started.
As of this version the functions in dlcompat should all be thread safe.
You can always get the latest version from opendarwin cvs:
cvs -d :pserver:anonymous@anoncvs.opendarwin.org:/cvs/od login
cvs -z3 -d :pserver:anonymous@anoncvs.opendarwin.org:/cvs/od \
co -d dlcompat proj/dlcompat
But remember that you will have to run autoconf to generate the configure
script.
It is hoped that this library will be useful, and as bug free as possible,
if you find any bugs please let us know about them so they can be fixed.
Please send bug reports to Peter O'Gorman <ogorman@users.sourceforge.net>
Thanks.