1/* Transfer data between file descriptors. Linux version.
2 Copyright (C) 2011-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library. If not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <sys/sendfile.h>
20#include <stddef.h>
21#include <errno.h>
22#include <sysdep.h>
23
24#ifndef __OFF_T_MATCHES_OFF64_T
25
26/* Send COUNT bytes from file associated with IN_FD starting at OFFSET to
27 descriptor OUT_FD. */
28ssize_t
29sendfile (int out_fd, int in_fd, off_t *offset, size_t count)
30{
31# ifdef __NR_sendfile
32 return INLINE_SYSCALL_CALL (sendfile, out_fd, in_fd, offset, count);
33# else
34 __off64_t off64;
35 int rc;
36
37 if (offset != NULL)
38 {
39 if (*offset < 0 || (off_t) (*offset + count) < 0)
40 {
41 __set_errno (EINVAL);
42 return -1;
43 }
44 off64 = *offset;
45 }
46
47 rc = INLINE_SYSCALL_CALL (sendfile64, out_fd, in_fd, offset ? &off64 : NULL,
48 count);
49 if (offset)
50 *offset = off64;
51 return rc;
52# endif
53}
54
55#endif
56

source code of glibc/sysdeps/unix/sysv/linux/sendfile.c