S_ISFIFO
#define S_ISFIFO(m) (((m) & S_IFMT) == S_IFIFO)
#define S_ISFIFO(mode) (((mode) & S_IFMT) == S_IFIFO)
#define S_ISFIFO(m) (((m) & S_IFMT) == S_IFIFO)
#define S_ISFIFO(m) (((m) & S_IFMT) == S_IFIFO)
#define S_ISFIFO(m) (((m)&S_IFMT) == S_IFIFO)