Another round of documentation.
Bug: N/A
Test: N/A
Change-Id: I1b818fbb36ddd6d084dee56828290c2717a0c9b0
diff --git a/libc/include/sys/sendfile.h b/libc/include/sys/sendfile.h
index 97432c0..60bbde8 100644
--- a/libc/include/sys/sendfile.h
+++ b/libc/include/sys/sendfile.h
@@ -26,8 +26,12 @@
* SUCH DAMAGE.
*/
-#ifndef _SYS_SENDFILE_H_
-#define _SYS_SENDFILE_H_
+#pragma once
+
+/**
+ * @file sys/sendfile.h
+ * @brief The sendfile() function.
+ */
#include <sys/cdefs.h>
#include <sys/types.h>
@@ -38,10 +42,21 @@
#if defined(__USE_FILE_OFFSET64)
ssize_t sendfile(int __out_fd, int __in_fd, off_t* __offset, size_t __count) __RENAME(sendfile64) __INTRODUCED_IN(21);
#else
+/**
+ * [sendfile(2)](http://man7.org/linux/man-pages/man2/sendfile.2.html) copies data directly
+ * between two file descriptors.
+ *
+ * Returns the number of bytes copied on success, and returns -1 and sets `errno` on failure.
+ *
+ * Available since API level 21.
+ */
ssize_t sendfile(int __out_fd, int __in_fd, off_t* __offset, size_t __count);
#endif
+
+/**
+ * Like sendfile() but allows using a 64-bit offset
+ * even from a 32-bit process without `__FILE_OFFSET_BITS=64`.
+ */
ssize_t sendfile64(int __out_fd, int __in_fd, off64_t* __offset, size_t __count) __INTRODUCED_IN(21);
__END_DECLS
-
-#endif