Programming

hi all

lyang0@lyang0:~$ ldd /bin/ls
linux-gate.so.1 => (0xb7f1c000)
librt.so.1 => /lib/tls/i686/cmov/librt.so.1 (0xb7f02000)
libselinux.so.1 => /lib/libselinux.so.1 (0xb7ee9000)
libacl.so.1 => /lib/libacl.so.1 (0xb7ee1000)
libc.so.6 => /lib/tls/i686/cmov/libc.so.6 (0xb7d92000)
libpthread.so.0 => /lib/tls/i686/cmov/libpthread.so.0 (0xb7d7a000)
/lib/ld-linux.so.2 (0xb7f1d000)
libdl.so.2 => /lib/tls/i686/cmov/libdl.so.2 (0xb7d76000)
libattr.so.1 => /lib/libattr.so.1 (0xb7d72000)

you can see libc.so.6 => /lib/tls/i686/cmov/libc.so.6,but how the linker know where to find it,I know the lib path can be find by using ld.so.conf, but /lib/tls/i386 is not in the ld.so.conf, please give me a light

thanks

The "tls" path is added by ld (the dynamic linker) in a compile-time search path. The TLS means that the library thread safe ("thread local storage"). There's some detailed information here. Anyway, the i386 is also a compile-time search path, and is platform-specific. This way i386 libraries and i686 libraries can be distinguished. If a program is compiled with the i386 instruction set, the linker will search for an i386 library. If it's compiled for the i686 instruction set, the linker will search first in i686, and then in i386.

The "cmov" refers to an instruction that is available in some -- but not all -- i686 architectures. So this is logically another compile-time search path, relevant to i686 libraries. (First look for the library in i686/cmov; if not found, look in i686/). More info found here.

hi otheus

I don't understand the compile time serch lib ,can you make a commet about complie time serch path and run time serch path,and where is the path defined .
one more thing I run
lyang0@lyang0:~$ gcc -print-search-dirs | grep libraries | tr '=:' '\n'
libraries

/usr/lib/gcc/i486-linux-gnu/4.2.3/
/usr/lib/gcc/i486-linux-gnu/4.2.3/
/usr/lib/gcc/i486-linux-gnu/4.2.3/../../../../i486-linux-gnu/lib/i486-linux-gnu/4.2.3/
/usr/lib/gcc/i486-linux-gnu/4.2.3/../../../../i486-linux-gnu/lib/../lib/
/usr/lib/gcc/i486-linux-gnu/4.2.3/../../../i486-linux-gnu/4.2.3/
/usr/lib/gcc/i486-linux-gnu/4.2.3/../../../../lib/
/lib/i486-linux-gnu/4.2.3/
/lib/../lib/
/usr/lib/i486-linux-gnu/4.2.3/
/usr/lib/../lib/
/usr/lib/gcc/i486-linux-gnu/4.2.3/../../../../i486-linux-gnu/lib/
/usr/lib/gcc/i486-linux-gnu/4.2.3/../../../
/lib/
/usr/lib/

I don't find the /lib/tls/i686 in the library serch paths
please help me to catch on this question
Thanks

Compile-time search path of "ld.so" the run-time dynamic linker, not the program you're trying to run. Do this at the command line:

Code:

LD_DEBUG=libs /bin/true

Replace "/bin/true" with the full path of the program you intend to run. You will see the paths that the dynamic linker searches for the dependencies.