The dlopen() function shall behave as specified in POSIX 1003.1-2001 (ISO/IEC 9945-2003), but with additional behaviors listed below.
If the file argument does not contain a slash character, then the system shall look for a library of that name in at least the following directories, and use the first one which is found:
The directories specified by the
DT_RPATH dynamic entry.
The directories specified in the
environment variable (which is a colon separated list of pathnames).
This step shall be skipped for setuid
and setgid executables.
A set of directories sufficient to contain the libraries specified in this standard.
Note: Traditionally, /lib and /usr/lib. This case would also cover cases in which the system used the mechanism of /etc/ld.so.conf and /etc/ld.so.cache to provide access.
Example: An application which is not linked against libm may choose to dlopen libm.