Full-Duplex VCBs

To identify definitions for the format 1 VCB that are needed for full-duplex conversations and to send and receive expedited data, the transaction program must define a compiler constant called WINAPPC_FORMAT_1 before including the WINAPPC.H header file. This can be achieved in C language as follows:

#define WINAPPC_FORMAT_1
#include <winappc.h>

If this constant is not defined, only the format zero versions of the VCBs will be accessible from the application.