pwrite: Work around HP-UX 11.11 bug.

* m4/pwrite.m4 (gl_FUNC_PWRITE): When pwrite exists, test whether it
works and set REPLACE_PWRITE if not.
* lib/pwrite.c (pwrite): Add an implementation that uses the system
function.
* doc/posix-functions/pwrite.texi: Document the HP-UX 11 bug.

1 files changed, 21 insertions, 3 deletions

diff --git a/lib/pwrite.c b/lib/pwrite.c
index 00714791c3..4a913571de 100644
--- a/lib/pwrite.c
+++ b/lib/pwrite.c
@@ -24,9 +24,25 @@
 
 #include <errno.h>
 
-#define __libc_lseek(f,o,w) lseek (f, o, w)
-#define __set_errno(Val) errno = (Val)
-#define __libc_write(f,b,n) write (f, b, n)
+#if HAVE_PWRITE
+
+ssize_t
+pwrite (int fd, const void *buf, size_t nbyte, off_t offset)
+# undef pwrite
+{
+  if (offset < 0)
+    {
+      errno = EINVAL;
+      return -1;
+    }
+  return pwrite (fd, buf, nbyte, offset);
+}
+
+#else
+
+# define __libc_lseek(f,o,w) lseek (f, o, w)
+# define __set_errno(Val) errno = (Val)
+# define __libc_write(f,b,n) write (f, b, n)
 
 /* Note: This implementation of pwrite is not multithread-safe.  */
 
@@ -62,3 +78,5 @@ pwrite (int fd, const void *buf, size_t nbyte, off_t offset)
 
   return result;
 }
+
+#endif