The ## operator in C

Question

What does ## do in C?

Example:

typedef struct
{
    unsigned int bit0:1;
    unsigned int bit1:1;
    unsigned int bit2:1;
    unsigned          


        

Answer 1

The operator ## concatenates two arguments leaving no blank spaces between them:

#define glue(a,b) a ## b
glue(c,out) << "test";