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Libtool

9.1 Building modules to dlopen

On some operating systems, a program symbol must be specially declared in order to be dynamically resolved with the dlsym (or equivalent) function.

Libtool provides the `-export-dynamic' and `-module' link flags (see section 4.2 Link mode), which do this declaration. You need to use these flags if you are linking an application program that dlopens other modules or a libtool library that will also be dlopened.

For example, if we wanted to build a shared library, `libhello', that would later be dlopened by an application, we would add `-module' to the other link flags:

burger$ libtool gcc -module -o libhello.la foo.lo \ hello.lo -rpath /usr/local/lib -lm burger$

If symbols from your executable are needed to satisfy unresolved references in a library you want to dlopen you will have to use the flag `-export-dynamic'. You should use `-export-dynamic' while linking the executable that calls dlopen:

burger$ libtool gcc -export-dynamic -o hell-dlopener main.o burger$