The header file cstypes.h contains type definitions (typedefs) for all of the Open Client and Open Server datatypes. The cstypes.h file is included in Client-Library applications using ctpublic.h—there is no need to include it explicitly.
An application declaring program variables uses these type definitions in its declaration section. For example:
CS_CHAR buffer[40];
CS_INT result_type, count;
CS_MONEY profit;