c++ - How to specify preference of library path? -

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i'm compiling c++ program using g++ , ld. have .so library want used during linking. however, library of same name exists in /usr/local/lib, , ld choosing library on 1 i'm directly specifying. how can fix this?

for examples below, library file /my/dir/libfoo.so.0. things i've tried don't work:

  • my g++ command g++ -g -wall -o my_binary -l/my/dir -lfoo bar.cpp
  • adding /my/dir beginning or end of $path en` variable
  • adding /my/dir/libfoo.so.0 argument g++

add path new library ld_library_path (it has different name on mac ...)

your solution should work using -l/my/dir -lfoo options, @ runtime use ld_library_path point location of library.

or

use rpath option via gcc linker - runtime library search path, used instead of looking in standard dir (gcc option):

-wl,-rpath,$(default_lib_install_path)

this temporary solution. linker first searches ld_library_path libraries before looking standard directories.

if don't want permanently update ld_library_path can on fly on command line:

ld_library_path=/some/custom/dir ./fooo

you can check libraries linker knows using (example):

/sbin/ldconfig -p | grep libpthread         libpthread.so.0 (libc6, os abi: linux 2.6.4) => /lib/libpthread.so.0

and can check library application using:

ldd foo         linux-gate.so.1 =>  (0xffffe000)         libpthread.so.0 => /lib/libpthread.so.0 (0xb7f9e000)         libxml2.so.2 => /usr/lib/libxml2.so.2 (0xb7e6e000)         librt.so.1 => /lib/librt.so.1 (0xb7e65000)         libm.so.6 => /lib/libm.so.6 (0xb7d5b000)         libc.so.6 => /lib/libc.so.6 (0xb7c2e000)         /lib/ld-linux.so.2 (0xb7fc7000)         libdl.so.2 => /lib/libdl.so.2 (0xb7c2a000)         libz.so.1 => /lib/libz.so.1 (0xb7c18000)

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