My question is about the link option, -l. Like, -lrt, We know that librt.a (or librt.so) is the actual file which is searched for. But i had a an experience and i saw that if there is no librt.a, other "rt" combinations are searched too, like , librtdm.a. I have a suggestion. please mention this fact in the GCC or LD manual. I have a question now. If I have several files like librtam.a, librtbm.a and librtcm.a and then i use -lrt, which one will be linked? (Or all of them?) /root> gcc --version gcc (GCC) 4.6.1 20110908 (Red Hat 4.6.1-9) Copyright (C) 2011 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. /root> rpm -qi binutils Name : binutils Relocations: (not relocatable) Version : 2.21.53.0.2 Vendor: Fedora Project Release : 1.fc17 Build Date: Mon 08 Aug 2011 20:53:40 IRDT Install Date: Wed 05 Oct 2011 16:05:39 IRST Build Host: x86-05.phx2.fedoraproject.org Group : Development/Tools Source RPM: binutils-2.21.53.0.2-1.fc17.src.rpm Size : 14303451 License: GPLv3+ Signature : (none) Packager : Fedora Project URL : http://sources.redhat.com/binutils Summary : A GNU collection of binary utilities