Preloaded shared libraries

The LDR_PRELOAD and LDR_PRELOAD64 environment variables make it possible for a process to preload shared libraries. The LDR_PRELOAD environment variable is for 32-bit processes, and the LDR_PRELOAD64 environment variable is for 64-bit processes.

During symbol resolution, the preloaded libraries listed in the environment variable will be searched first for every imported symbol, and only when a symbol is not found will the normal search be used. Preempting of symbols from preloaded libraries works for both AIX® default linking and run-time linking. Deferred symbol resolution is unchanged.

For more information on these environment variables, see Miscellaneous tunable parameters.