The -d option lets you define up to eight symbolic constants on the command line. The syntax is as follows:
-d defname[=value]
In the previous example, defname is a name, and value is an integer constant, or an expression. The -d option is useful for passing conditional-compilation flags to the RC preprocessor.
The following example specifies a Japanese code-page identifier and also defines two symbolic constants to be passed to the preprocessor as conditional-compilation flags.
rc -cp 942 -d DEBUG -d VERSION=2 example
Note: RC creates many temporary files and writes them to the directory indicated by the TMP or TEMP environment variable. If RC cannot write these temporary files to this directory, it writes them to the current directory.