Using Parentheses in Define Preprocessor Statements

Question

So I was wondering when is to use

 #define xxx (yyy)

vs

 #define xxx  yyy

My project includes a files tha

Answer 1

An important thing to remember is that the preprocessor simply expands macros. For example, if you had the following lines:

#define AD0_COMPARETIME_1    (AD0_ADMD_CT)
#define AD0_COMPARETIME_2    AD0_ADMD_CT

num_1 = AD0_COMPARETIME_1;
num_2 = AD0_COMPARETIME_2;

After the first expansion you'd have this:

num_1 = (AD0_ADMD_CT);
num_2 = AD0_ADMD_CT;

And after the second expansion you'd have this:

num_1 = ((IO_AD1.ADMD.bit.CT));
num_2 = (IO_AD1.ADMD.bit.CT);

A problem may arise, as stated in other answers, when an expression is expanded.