S_ISREG
#define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
#define S_ISREG(mode) (((mode) & S_IFMT) == S_IFREG)
#define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)
#define S_ISREG(m) (((m) & S_IFMT) == S_IFREG)