libio: Eliminate _IO_stdin, _IO_stdout, _IO_stderr

These variables are only used to determine if a stdio stream is
a pre-allocated stream, but it is possible to do so by comparing
a FILE * to all pre-allocated stream objects.  As a result, it is
not necessary to keep those pointers in separate variables.

Behavior with symbol interposition is unchanged because _IO_stdin_,
_IO_stdout_, _IO_stderr_ are exported, and refer to objects outside of
libc if symbol interposition or copy relocations are involved.  (The
removed variables _IO_stdin, _IO_stdout, _IO_stderr were not exported,
of course.)

1 files changed, 4 insertions, 5 deletions

diff --git a/libio/stdfiles.c b/libio/stdfiles.c
index 605e006474..9c779b47eb 100644
--- a/libio/stdfiles.c
+++ b/libio/stdfiles.c
@@ -25,11 +25,10 @@
    in files containing the exception.  */
 
 
-/* This file provides definitions of _IO_stdin, _IO_stdout, and _IO_stderr
-   for C code.  Compare stdstreams.cc.
-   (The difference is that here the vtable field is set to 0,
-   so the objects defined are not valid C++ objects.  On the other
-   hand, we don't need a C++ compiler to build this file.) */
+/* This file provides definitions of _IO_2_1_stdin_, _IO_2_1_stdout_,
+   and _IO_2_1_stderr_, the default values of stdin, stdout, stderr.
+   See oldstdfiles.c for glibc 2.0 legacy definitions without wide
+   character support.  */
 
 #include "libioP.h"