For protected-mode Windows applications, use the /GA option to optimize the entry/exit code of all far functions explicitly marked as __export.
For Windows dynamic-link libraries (DLLs) designed for protected mode, use the /GD option to optimize the entry/exit code of all far functions explicitly marked as __export.
When used instead of either the /GW or the /Gw option, both the /GA option and the /GD option save 10 bytes and 7 instructions for each function call. For /GA, use of __export adds an additional 6 bytes and 4 instructions to a function call; /GD with __export adds an additional 6 bytes and 7 instructions to a function call. The code generated in all four cases is smaller than that generated by /Gw or /GW. Note that in all four cases, you can also use the Generate 80286 Code option (/G2) to save an additional 4 bytes.
Both the /GA and /GD options define the _WINDOWS constant, and the /GD option defines the _WINDLL constant. The /GA option specifies use of both mLIBCfW.LIB and the Windows API library. The /GD option specifies use of both mDLLCfW.LIB and the Windows API library. You cannot specify the /Gw, /GW, or /Gq options with either the /GA or the /GD options.