Linux Threads Question:

This is one system administrator's point of view why
LD_LIBRARY_PATH, as frequently used, is bad. This is written
from a SunOS 4.x/5.x (and to some extent Linux) point of
view, but this also applies to most other UNIXes.

LD_LIBRARY_PATH is an environment variable you set to give
the run-time shared library loader (ld.so) an extra set of
directories to look for when searching for shared libraries.
Multiple directories can be listed, separated with a colon
(:). This list is prepended to the existing list of
compiled-in loader paths for a given executable, and any
system default loader paths.

For security reasons, LD_LIBRARY_PATH is ignored at runtime
for executables that have their setuid or setgid bit set.
This severely limits the usefulness of LD_LIBRARY_PATH.