Index: uspace/lib/posix/source/unistd.c
===================================================================
--- uspace/lib/posix/source/unistd.c	(revision b8e72fd18870c8da72ae4479760748f02fd51136)
+++ uspace/lib/posix/source/unistd.c	(revision e3480d5412afdfabbc3498e0ae4532b6f1d0a749)
@@ -221,4 +221,16 @@
 {
 	return errnify(write, fildes, buf, nbyte);
+}
+
+/**
+ * Reposition read/write file offset
+ *
+ * @param fildes File descriptor of the opened file.
+ * @return Upon successful completion, returns the resulting offset
+ *         as measured in bytes from the beginning of the file, -1 otherwise.
+ */
+posix_off_t posix_lseek(int fildes, posix_off_t offset, int whence)
+{
+	return errnify(lseek, fildes, offset, whence);
 }