libw32dl — dlopen and friends for mingw32

• is really easy to incorporate into any program;
• is tiny (adding about 700 bytes to the main executable and each shared object);
• properly finds symbols 'defined' in the main .exe file but which in reality live in an implicitly-loaded dll [Note 1];
• invokes _init() and _fini() at the appropriate times, if it can;
• makes symbols in RTLD_GLOBALly-opened modules available to the main executable and to all shared objects via RTLD_DEFAULT, regardless of where (in the executable or in a shared object) the module is dlopen()ed;
• pays lip service to RTLD_LOCAL and RTLD_GLOBAL when searching the RTLD_DEFALT 'global namespace'.

[Note 1]

The thing that infuriated me into writing this library was that 'nm' showed printf as a defined, exported symbol in my main.exe file but GetProcAdddress(GetModuleHandle(0), "printf") could not be persuaded to find it. Grrrr.

There is no documentation, just the notes below and an example program in the 'test' directory (type 'make test' in the top-level directory to run it).

Download the source code: libw32dl-1.0.tar.gz
Browse the source code: libw32dl-1.0

Using the library

For the main executable:

• include the header "w32dlfcn.h" in any source file that uses the dlopen API;
• include libw32dl.a when linking the final executable;
• arrange for the executable to export all the symbols that might be looked up by dlsym. The simple-minded way to do this (and hence my preferred solution) is to pass -Wl,--export-all-symbols to cc in the link command.

• include the header "w32dlfcn.h" in any source file that uses the dlopen API;
• include libw32dl.a when linking the final shared object;
• make sure -shared is passed to cc in the link command;
• arrange for the shared object to export all the symbols that might be looked up by dlsym. The simple-minded way to do this (and hence my preferred solution) is to pass -Wl,--export-all-symbols to cc in the link command.

libw32dl is distributed under the MIT license. It will not infect your project with a contagious disease if you decide to use and/or modify it.

If you fix any bugs, please send your fixes to Ian Piumarta by email at 'first-name at last-name dot com'. Thanks!