CODEWITHSUNDEEP
macosshared-librariesdlopen
peastman
peastman

Reputation: 1279

dlopen() with dependencies between libraries

My program uses plugins, that are loaded dynamically with dlopen(). The locations of these plugins can be arbitrary, so they aren't necessarily in the library path. In some cases, one plugin needs to depend on another plugin. So if A and B are dynamic libraries, I'll first load A, then load B which uses symbols defined in A.

My reading of the dlopen() documentation implies that if I specify RTLD_GLOBAL this should all work. But it doesn't. When I call dlopen() on the second library, it fails with an error saying it couldn't find the first one (which had already been loaded with dlopen()):

Error loading library /usr/local/openmm/lib/plugins/libOpenMMRPMDOpenCL.dylib: dlopen(/usr/local/openmm/lib/plugins/libOpenMMRPMDOpenCL.dylib, 9): Library not loaded: libOpenMMOpenCL.dylib
Referenced from: /usr/local/openmm/lib/plugins/libOpenMMRPMDOpenCL.dylib
Reason: image not found

How can I make this work?

Upvotes: 4

Views: 3672

Answers (1)

Doug
Doug

Reputation: 35136

See this answer here: dlopen() error image not found

If you modify the library to have an install name of @rpath/blah.dylib, you'll be able to do this.

Edit:

I'm also using cmake, use this:

set_target_properties(${MY_LIB} PROPERTIES BUILD_WITH_INSTALL_RPATH 1 INSTALL_NAME_DIR "@rpath")

This doesn't break things on other platforms either, but make sure you haven't called CMAKE_SKIP_RPATH or it won't be invoked.

Upvotes: 1

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