PR70975 Pass valid offset argument to sendfile

	PR libstdc++/70975
	* src/filesystem/ops.cc (do_copy_file) [_GLIBCXX_USE_SENDFILE]:
	Pass non-null pointer to sendfile for offset argument.

From-SVN: r241629

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 50f5837..6a06101 100644 (file)
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,9 @@
+2016-10-27  Uros Bizjak  <ubizjak@gmail.com>
+
+       PR libstdc++/70975
+       * src/filesystem/ops.cc (do_copy_file) [_GLIBCXX_USE_SENDFILE]:
+       Pass non-null pointer to sendfile for offset argument.
+
 2016-10-27  Jonathan Wakely  <jwakely@redhat.com>
 
        * testsuite/ext/random/uniform_inside_sphere_distribution/cons/

diff --git a/libstdc++-v3/src/filesystem/ops.cc b/libstdc++-v3/src/filesystem/ops.cc
index 9abcee0..8ed0a10 100644 (file)
--- a/libstdc++-v3/src/filesystem/ops.cc
+++ b/libstdc++-v3/src/filesystem/ops.cc
@@ -444,7 +444,8 @@ namespace
       }
 
 #ifdef _GLIBCXX_USE_SENDFILE
-    const auto n = ::sendfile(out.fd, in.fd, nullptr, from_st->st_size);
+    off_t offset = 0;
+    const auto n = ::sendfile(out.fd, in.fd, &offset, from_st->st_size);
     if (n < 0 && (errno == ENOSYS || errno == EINVAL))
       {
 #endif