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authorZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
committerZack Weinberg <zackw@panix.com>2017-06-08 15:39:03 -0400
commit5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 (patch)
tree4470480d904b65cf14ca524f96f79eca818c3eaf /REORG.TODO/sysdeps/posix/pwrite64.c
parent199fc19d3aaaf57944ef036e15904febe877fc93 (diff)
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Prepare for radical source tree reorganization. zack/build-layout-experiment
All top-level files and directories are moved into a temporary storage
directory, REORG.TODO, except for files that will certainly still
exist in their current form at top level when we're done (COPYING,
COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which
are moved to the new directory OldChangeLogs, instead), and the
generated file INSTALL (which is just deleted; in the new order, there
will be no generated files checked into version control).
Diffstat (limited to 'REORG.TODO/sysdeps/posix/pwrite64.c')
-rw-r--r--REORG.TODO/sysdeps/posix/pwrite64.c62
1 files changed, 62 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/posix/pwrite64.c b/REORG.TODO/sysdeps/posix/pwrite64.c
new file mode 100644
index 0000000000..601a268f59
--- /dev/null
+++ b/REORG.TODO/sysdeps/posix/pwrite64.c
@@ -0,0 +1,62 @@
+/* Write block to given position in file without changing file pointer.
+   POSIX version.
+   Copyright (C) 1997-2017 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <errno.h>
+#include <unistd.h>
+
+/* Note: This implementation of pwrite64 is not multithread-safe.  */
+
+ssize_t
+__libc_pwrite64 (int fd, const void *buf, size_t nbyte, off64_t offset)
+{
+  /* Since we must not change the file pointer preserve the value so that
+     we can restore it later.  */
+  int save_errno;
+  ssize_t result;
+  off64_t old_offset = __libc_lseek64 (fd, 0, SEEK_CUR);
+  if (old_offset == (off64_t) -1)
+    return -1;
+
+  /* Set to wanted position.  */
+  if (__libc_lseek64 (fd, offset, SEEK_SET) == (off64_t) -1)
+    return -1;
+
+  /* Write out the data.  */
+  result = __libc_write (fd, buf, nbyte);
+
+  /* Now we have to restore the position.  If this fails we have to
+     return this as an error.  But if the writing also failed we
+     return this error.  */
+  save_errno = errno;
+  if (__libc_lseek64 (fd, old_offset, SEEK_SET) == (off64_t) -1)
+    {
+      if (result == -1)
+	__set_errno (save_errno);
+      return -1;
+    }
+  __set_errno (save_errno);
+
+  return result;
+}
+#ifndef __libc_pwrite64
+weak_alias (__libc_pwrite64, __pwrite64)
+libc_hidden_weak (__pwrite64)
+weak_alias (__libc_pwrite64, pwrite64)
+#endif