#ifdef name
The #ifdef directive controls conditional compilation of the resource file by checking the specified name. If the name has been defined by using a #define directive or by using the -d command-line option with the Resource Compiler, #ifdef directs the compiler to continue with the statement immediately after the #ifdef directive. If the name has not been defined, #ifdef directs the compiler to skip all statements up to the next #endif directive.
name
Specifies the name to be checked by the directive.
This example compiles the BITMAP statement only if the name “Debug” is defined:
#ifdef Debug
BITMAP 1 errbox.bmp
#endif
#define, #endif, #if, #ifndef, #undef