c - Sending parameter to a #define -


i wonder know possible send parameter #define macro selecting different output

for example:

#define row(1) lpc_gpio0 #define row(2) lpc_gpio3 #define row(3) lpc_gpio2

then in code create loop sending parameter 

row(x)

this macro syntax doesn't exist.

moreover, can't possibly exist, because macros expanded before compiler compiles code. if x isn't compile time constant, there never way determine replace in source code macro invocation.

if need index values, use array, e.g. (assuming these constants integers):

static int rows[] = { 0, lpc_gpio0, lpc_gpio3, lpc_gpio2 };

writing

rows[x]

would have effect seem have expected invalid macro syntax.


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