Merge "<sys/select.h>: use __builtin_memset rather than writing our own." into main
diff --git a/libc/include/sys/select.h b/libc/include/sys/select.h
index 84c2621..437a234 100644
--- a/libc/include/sys/select.h
+++ b/libc/include/sys/select.h
@@ -44,7 +44,7 @@
typedef unsigned long fd_mask;
/**
- * The limit on the largest fd that can be used with this API.
+ * The limit on the largest fd that can be used with fd_set.
* Use <poll.h> instead.
*/
#define FD_SETSIZE 1024
@@ -52,6 +52,9 @@
/**
* The type of a file descriptor set. Limited to 1024 fds.
+ * The underlying system calls do not have this limit,
+ * and callers can allocate their own sets with calloc().
+ *
* Use <poll.h> instead.
*/
typedef struct {
@@ -60,30 +63,27 @@
#define __FDELT(fd) ((fd) / NFDBITS)
#define __FDMASK(fd) (1UL << ((fd) % NFDBITS))
-#define __FDS_BITS(type,set) (__BIONIC_CAST(static_cast, type, set)->fds_bits)
-
-/* Inline loop so we don't have to declare memset. */
-#define FD_ZERO(set) \
- do { \
- size_t __i; \
- for (__i = 0; __i < sizeof(fd_set)/sizeof(fd_mask); ++__i) { \
- (set)->fds_bits[__i] = 0; \
- } \
- } while (0)
+#define __FDS_BITS(type, set) (__BIONIC_CAST(static_cast, type, set)->fds_bits)
void __FD_CLR_chk(int, fd_set* _Nonnull , size_t);
void __FD_SET_chk(int, fd_set* _Nonnull, size_t);
int __FD_ISSET_chk(int, const fd_set* _Nonnull, size_t);
-#define __FD_CLR(fd, set) (__FDS_BITS(fd_set*,set)[__FDELT(fd)] &= ~__FDMASK(fd))
-#define __FD_SET(fd, set) (__FDS_BITS(fd_set*,set)[__FDELT(fd)] |= __FDMASK(fd))
-#define __FD_ISSET(fd, set) ((__FDS_BITS(const fd_set*,set)[__FDELT(fd)] & __FDMASK(fd)) != 0)
+/** FD_CLR() with no bounds checking for users that allocated their own set. */
+#define __FD_CLR(fd, set) (__FDS_BITS(fd_set*, set)[__FDELT(fd)] &= ~__FDMASK(fd))
+/** FD_SET() with no bounds checking for users that allocated their own set. */
+#define __FD_SET(fd, set) (__FDS_BITS(fd_set*, set)[__FDELT(fd)] |= __FDMASK(fd))
+/** FD_ISSET() with no bounds checking for users that allocated their own set. */
+#define __FD_ISSET(fd, set) ((__FDS_BITS(const fd_set*, set)[__FDELT(fd)] & __FDMASK(fd)) != 0)
-/** Removes `fd` from the given set. Use <poll.h> instead. */
+/** Removes all 1024 fds from the given set. Use <poll.h> instead. */
+#define FD_ZERO(set) __builtin_memset(set, 0, sizeof(*__BIONIC_CAST(static_cast, const fd_set*, set)))
+
+/** Removes `fd` from the given set. Limited to fds under 1024. Use <poll.h> instead. */
#define FD_CLR(fd, set) __FD_CLR_chk(fd, set, __bos(set))
-/** Adds `fd` to the given set. Use <poll.h> instead. */
+/** Adds `fd` to the given set. Limited to fds under 1024. Use <poll.h> instead. */
#define FD_SET(fd, set) __FD_SET_chk(fd, set, __bos(set))
-/** Tests whether `fd` is in the given set. Use <poll.h> instead. */
+/** Tests whether `fd` is in the given set. Limited to fds under 1024. Use <poll.h> instead. */
#define FD_ISSET(fd, set) __FD_ISSET_chk(fd, set, __bos(set))
/**