How to print the ld(linker) search path
You can do this by executing the following command:
ld --verbose | grep SEARCH_DIR | tr -s ' ;' \\012
gcc passes a few extra -L paths to the linker, which you can list with the following command:
gcc -print-search-dirs | sed '/^lib/b 1;d;:1;s,/[^/.][^/]*/\.\./,/,;t 1;s,:[^=]*=,:;,;s,;,; ,g' | tr \; \\012
The answers suggesting to use ld.so.conf and ldconfig are not correct because they refer to the paths searched by the runtime dynamic linker (i.e. whenever a program is executed), which is not the same as the path searched by ld (i.e. whenever a program is linked).
On Linux, you can use ldconfig
, which maintains the ld.so configuration and cache, to print out the directories search by ld.so
with
ldconfig -v 2>/dev/null | grep -v ^$'\t'
ldconfig -v
prints out the directories search by the linker (without a leading tab) and the shared libraries found in those directories (with a leading tab); the grep
gets the directories. On my machine, this line prints out
/usr/lib64/atlas:
/usr/lib/llvm:
/usr/lib64/llvm:
/usr/lib64/mysql:
/usr/lib64/nvidia:
/usr/lib64/tracker-0.12:
/usr/lib/wine:
/usr/lib64/wine:
/usr/lib64/xulrunner-2:
/lib:
/lib64:
/usr/lib:
/usr/lib64:
/usr/lib64/nvidia/tls: (hwcap: 0x8000000000000000)
/lib/i686: (hwcap: 0x0008000000000000)
/lib64/tls: (hwcap: 0x8000000000000000)
/usr/lib/sse2: (hwcap: 0x0000000004000000)
/usr/lib64/tls: (hwcap: 0x8000000000000000)
/usr/lib64/sse2: (hwcap: 0x0000000004000000)
The first paths, without hwcap
in the line, are either built-in or read from /etc/ld.so.conf.
The linker can then search additional directories under the basic library search path, with names like sse2
corresponding to additional CPU capabilities.
These paths, with hwcap
in the line, can contain additional libraries tailored for these CPU capabilities.
One final note: using -p
instead of -v
above searches the ld.so
cache instead.
I'm not sure that there is any option for simply printing the full effective search path.
But: the search path consists of directories specified by -L
options on the command line, followed by directories added to the search path by SEARCH_DIR("...")
directives in the linker script(s). So you can work it out if you can see both of those, which you can do as follows:
If you're invoking ld
directly:
- The
-L
options are whatever you've said they are. - To see the linker script, add the
--verbose
option. Look for theSEARCH_DIR("...")
directives, usually near the top of the output. (Note that these are not necessarily the same for every invocation ofld
-- the linker has a number of different built-in default linker scripts, and chooses between them based on various other linker options.)
If you're linking via gcc
:
- You can pass the
-v
option togcc
so that it shows you how it invokes the linker. In fact, it normally does not invokeld
directly, but indirectly via a tool calledcollect2
(which lives in one of its internal directories), which in turn invokesld
. That will show you what-L
options are being used. - You can add
-Wl,--verbose
to thegcc
options to make it pass--verbose
through to the linker, to see the linker script as described above.