Hi, After compiling my project, following library functions are listed in the m51 file. C:\KEIL\C51\LIB\C51L.LIB (?C_INIT) C:\KEIL\C51\LIB\C51L.LIB (?C?COPY) C:\KEIL\C51\LIB\C51L.LIB (?C?CLDPTR) C:\KEIL\C51\LIB\C51L.LIB (?C?CLDOPTR) C:\KEIL\C51\LIB\C51L.LIB (?C?CSTPTR) C:\KEIL\C51\LIB\C51L.LIB (?C?CSTOPTR) Where can I get the sizes of these functions?. with regards Rajesh