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gnu ld searchpath

Vinitha Vijayan vinitha.vijayann@gmail.com
Thu May 28 11:53:00 GMT 2015 
Hi,
Sorry if I am posting to a wrong mailing list.

As per the gnu ld documentation,
" The linker uses the following search paths to locate required shared
libraries:
1. Any directories specified by -rpath-link options.
2. Any directories specified by -rpath options. The difference between
-rpath and -rpath-link is that directories specified by -rpath options
are included in the executable and used at runtime, whereas the
-rpath-link option is only effective at link time. Searching -rpath in
this way is only supported by native linkers and cross linkers which
have been configured with the --with-sysroot option.
3. On an ELF system, for native linkers, if the -rpath and -rpath-link
options were not used, search the contents of the environment variable
LD_RUN_PATH.
4. On SunOS, if the -rpath option was not used, search any directories
specified using -L options.
5. For a native linker, search the contents of the environment
variable LD_LIBRARY_PATH.
6. For a native ELF linker, the directories in DT_RUNPATH or DT_RPATH
of a shared library are searched for shared libraries needed by it.
The DT_RPATH entries are ignored if DT_RUNPATH entries exist.
7. The default directories, normally /lib and /usr/lib.
8. For a native linker on an ELF system, if the file /etc/ld.so.conf
exists, the list of directories found in that file.

I have doubt regarding the last point i.e, "8. For a native linker on
an ELF system, if the file /etc/ld.so.conf exists, the list of
directories found in that file."

Does this mean, if I have placed a local shared lib " libfoo.so"  in a
local path e.g, /usr/local/foo/lib  and add this path in
/etc/ld.so.conf  or /etc/ld.so.conf.d/libfoo.conf, the following will
work ?

gcc main.c  -lfoo

The above  doesn't seems to work in with a native linker in a native
armhf environment, unless I pass -L/usr/local/foo/lib in the command
line.

Is this the expected behavior for gnu ld ? And ld.so.conf file entries
only affect runtime linker (ld-linux*.so) searchpaths ?

Regards,
Vinitha Vijayan
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