I am using gcc 4.4.3 on ubuntu. I installed cmph library tools 0.9-1 using command sudo apt-get install libcmph-tools Now, when I tried to compile example program vector_adapter_ex1.c , gcc is able to detect cmph.h library in its include file but is showing multiple errors like vector_adapter_ex1.c:(.text+0x93): undefined reference to cmph_io_vector_adapter' vector_adapter_ex1.c:(.text+0xa3): undefined reference tocmph_config_new' vector_adapter_ex1.c:(.text+0xbb): undefined reference to cmph_config_set_algo' vector_adapter_ex1.c:(.text+0xcf): undefined reference tocmph_config_set_mphf_fd' even though, these are all defined in the source code of the cmph library. Could anyone tell the error that might have occurred or suggest an alternate method to go about building minimal perfect hash functions.