Hai, Iam new to KEIL i created .LIB file with some funtions. and i Created .Header file with all extern declaration for the funtions which are in .Lib file i creat .LIB file and .H file i included the .h file in main.c and iam using functions from LIB and when i compile its showing "UNRESOLVED EXTERNAL SYMBOL" how to avoid this, can u send a sample .LIB file and .H file to know how to declare and write the funtions in .LIB file and .H file. mail: tuan2101@yahoo.com thanks van tuan