1 files changed, 92 insertions, 0 deletions
diff --git a/newlib/libc/unix/pwrite.c b/newlib/libc/unix/pwrite.c
new file mode 100644
index 000000000..2d672bfbe
--- /dev/null
+++ b/newlib/libc/unix/pwrite.c
@@ -0,0 +1,92 @@
+/*
+FUNCTION
+<<pwrite>>---write a file from specified position
+
+INDEX
+	pwrite
+INDEX
+	_pwrite_r
+
+ANSI_SYNOPSIS
+	#include <unistd.h>
+	ssize_t pwrite(int <[fd]>, const void *<[buf]>, 
+                       size_t <[n]>, off_t <[off]>);
+	ssize_t _pwrite_r(struct _reent *<[rptr]>, int <[fd]>, 
+                          const void *<[buf]>, size_t <[n]>, off_t <[off]>);
+
+TRAD_SYNOPSIS
+	#include <unistd.h>
+	ssize_t pwrite(<[fd]>, <[buf]>, <[n]>, <[off]>)
+	int <[fd]>;
+	const void *<[buf]>;
+	size_t <[n]>;
+	off_t <[off]>;
+
+	ssize_t _pwrite_r(<[rptr]>, <[fd]>, <[buf]>, <[n]>, <[off]>)
+	struct _reent *<[rptr]>;
+	int <[fd]>;
+	const void *<[buf]>;
+	size_t <[n]>;
+	off_t <[off]>;
+
+DESCRIPTION
+The <<pwrite>> function is similar to <<write>>.  One difference is that
+<<pwrite>> has an additional parameter <[off]> which is the offset to
+position in the file before writing.  The function also differs in that
+the file position is unchanged by the function (i.e. the file position
+is the same before and after a call to <<pwrite>>).
+
+The <<_pwrite_r>> function is the same as <<pwrite>>, only a reentrant
+struct pointer <[rptr]> is provided to preserve reentrancy.
+
+RETURNS
+<<pwrite>> returns the number of bytes written or <<-1>> if failure occurred.
+
+PORTABILITY
+<<pwrite>> is non-ANSI and is specified by the Single Unix Specification.
+
+Supporting OS subroutine required: <<write>>, <<lseek>>.
+*/
+
+#include <_ansi.h>
+#include <unistd.h>
+#include <reent.h>
+
+ssize_t
+_DEFUN (pwrite_r, (rptr, fd, buf, n, off),
+     struct _reent *rptr _AND
+     int fd _AND
+     _CONST _PTR buf _AND
+     size_t n _AND
+     off_t off)
+{
+  off_t cur_pos;
+  _READ_WRITE_RETURN_TYPE num_written;
+  
+  if ((cur_pos = _lseek_r (rptr, fd, 0, SEEK_CUR)) == (off_t)-1)
+    return -1;
+
+  if (_lseek_r (rptr, fd, off, SEEK_SET) == (off_t)-1)
+    return -1;
+
+  num_written = _write_r (rptr, fd, buf, n);
+
+  if (_lseek_r (rptr, fd, cur_pos, SEEK_SET) == (off_t)-1)
+    return -1;
+
+  return (ssize_t)num_written;
+}
+
+#ifndef _REENT_ONLY
+
+ssize_t
+_DEFUN (pwrite, (fd, buf, n, off),
+     int fd _AND
+     _CONST _PTR buf _AND
+     size_t n _AND
+     off_t off)
+{
+  return _pwrite_r (_REENT, fd, buf, n, off);
+}
+
+#endif