why isn't gcc passing macro value from the command line?

Question

I'm trying to pass the value of a C macro to the preprocessor with the -Dmacro=value option of gcc. However, it doesn't do what i expect. This is the basics of my code:

#define T0 0
#define T1 0
#define T2 0
#define T3 0

int main(){

    int f[9];

    start(f[T0], f[T1], f[T2], f[T3]);

    return 0;
}

Running gcc -DT3=1 -E shows the preprocessor does not replace the original value of T3. What am i missing, and how can the value be passed properly?

Answer 1

Afaik that switch will define a macro, but your code then overrides it back to 0. Remove that define from your code or surround it with ifdef and it should be fine.