Well! I downloaded the latest glibc and working on that. In that I want to know the exact use of rtld.c file. Its is in the elf directory. So what happpends to ld.so when a make is done in elf directory. I inserted my own function in rtld.c file and did a make in elf directory. Iam trying to call that function in one my program located in some other directory. For that i'm using the make file as follows CC = gcc CFLAGS = -Wall all: test-ld test-reg test.o: test.c gcc -c test.c test-ld: test.o /trutta2/srg/projects/dynamic-loader/glibc-2.2.4/elf/ld.so gcc -Wl,-dynamic-linker,/trutta2/srg/projects/dynamic-loader/glibc-2.2.4/elf/ld.so test.o -o test-ld -ldl test-reg: test.o gcc test.o -o test-reg But it gives me the following error gcc test.o -o test-reg test.o: In function `main': test.o(.text+0x11): undefined reference to `dlopen' test.o(.text+0x41): undefined reference to `dlerror' test.o(.text+0x51): undefined reference to `dlsym' test.o(.text+0x5c): undefined reference to `dlerror' test.o(.text+0x91): undefined reference to `dlclose' collect2: ld returned 1 exit status make: *** [test-reg] Error 1 I was wondering what's happening. Thanks in advance Navin -- Navin Kumar Vedagiri Graduate Teaching Assistant Department Of Computer Science, New Mexico State University, Las Cruces, NM - 88001 Res: (505) 532 1273 Off: (505) 646 3198