the error message you got depends from the C compiler you are using, for instance COSMIC, and not from the IDE STVD7. It means that a C function you defined in a ''.c'' module does not have a correspondant function declaration (the so called 'prototype') somewhere written in the program code (tipically the latter stays in a ''.h'' header file). I kindly suggest you to read further the C language manual normally given with the compiler tool (for Cosmic this is true), where a lot of examples often follow the definition of ANSI C statement. Best regards, Tanio