The Compiler directive P64 enables you to create a program that can be run on a 64-bit development system or on COBOL Server in 64-bit mode. If you do not use the P64 directive when you compile your program, the program can only be run on a 32-bit development system, or on COBOL Server in 32-bit mode. Therefore, if you have developed an application on a 32-bit development system, you must recompile it with the P64 directive set, if you want to migrate it using COBOL Server in 64-bit mode.
The P64 directive is set by default if you compile using the cob64 command, or using the cob command with the 64-bit working mode.
The P64 directive is set by default if you choose 64 bit in Platform Target on the COBOL page of your build configuration options.