S_ISSOCK
#define S_ISSOCK(m) (((m) & S_IFMT) == S_IFSOCK)
#define S_ISSOCK(mode) (((mode) & S_IFMT) == S_IFSOCK)
#define S_ISSOCK(m) (((m) & S_IFMT) == S_IFSOCK)
#define S_ISSOCK(m) (((m) & S_IFMT) == S_IFSOCK)
#define S_ISSOCK(m) (((m)&S_IFMT) == S_IFSOCK)