S_ISLNK
#define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
#define S_ISLNK(mode) (((mode) & S_IFMT) == S_IFLNK)
#define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
#define S_ISLNK(m) (((m) & S_IFMT) == S_IFLNK)
#define S_ISLNK(m) (((m)&S_IFMT) == S_IFLNK)