Re: [PATCH 10/20] unlocked stdio extensions

[Yaakov Selkowitz <yselkowi at redhat dot com>]

Index: libc/stdio/fputc.c
===================================================================
RCS file: /cvs/src/src/newlib/libc/stdio/fputc.c,v
retrieving revision 1.8
diff -u -p -r1.8 fputc.c
--- libc/stdio/fputc.c	29 Apr 2013 21:06:23 -0000	1.8
+++ libc/stdio/fputc.c	17 Dec 2014 18:27:03 -0000
@@ -17,32 +17,55 @@
 
 /*
 FUNCTION
-<<fputc>>---write a character on a stream or file
+<<fputc>>, <<fputc_unlocked>>---write a character on a stream or file
 
 INDEX
 	fputc
 INDEX
+	fputc_unlocked
+INDEX
 	_fputc_r
+INDEX
+	_fputc_unlocked_r
 
 ANSI_SYNOPSIS
 	#include <stdio.h>
 	int fputc(int <[ch]>, FILE *<[fp]>);
 
+	#define _BSD_SOURCE
+	#include <stdio.h>
+	int fputc_unlocked(int <[ch]>, FILE *<[fp]>);
+
 	#include <stdio.h>
 	int _fputc_r(struct _rent *<[ptr]>, int <[ch]>, FILE *<[fp]>);
 
+	#include <stdio.h>
+	int _fputc_unlocked_r(struct _rent *<[ptr]>, int <[ch]>, FILE *<[fp]>);
+
 TRAD_SYNOPSIS
 	#include <stdio.h>
 	int fputc(<[ch]>, <[fp]>)
 	int <[ch]>;
 	FILE *<[fp]>;
 
+	#define _BSD_SOURCE
+	#include <stdio.h>
+	int fputc_unlocked(<[ch]>, <[fp]>)
+	int <[ch]>;
+	FILE *<[fp]>;
+
 	#include <stdio.h>
 	int _fputc_r(<[ptr]>, <[ch]>, <[fp]>)
 	struct _reent *<[ptr]>;
 	int <[ch]>;
 	FILE *<[fp]>;
 
+	#include <stdio.h>
+	int _fputc_unlocked_r(<[ptr]>, <[ch]>, <[fp]>)
+	struct _reent *<[ptr]>;
+	int <[ch]>;
+	FILE *<[fp]>;
+
 DESCRIPTION
 <<fputc>> converts the argument <[ch]> from an <<int>> to an
 <<unsigned char>>, then writes it to the file or stream identified by
@@ -56,8 +79,18 @@ oadvances by one.
 
 For a macro version of this function, see <<putc>>.
 
-The <<_fputc_r>> function is simply a reentrant version of <<fputc>>
-that takes an additional reentrant structure argument: <[ptr]>.
+<<fputc_unlocked>> is a non-thread-safe version of <<fputc>>.
+<<fputc_unlocked>> may only safely be used within a scope
+protected by flockfile() (or ftrylockfile()) and funlockfile().  This
+function may safely be used in a multi-threaded program if and only
+if they are called while the invoking thread owns the (FILE *)
+object, as is the case after a successful call to the flockfile() or
+ftrylockfile() functions.  If threads are disabled, then
+<<fputc_unlocked>> is equivalent to <<fputc>>.
+
+The <<_fputc_r>> and <<_fputc_unlocked_r>> functions are simply reentrant
+versions of the above that take an additional reentrant structure
+argument: <[ptr]>.
 
 RETURNS
 If successful, <<fputc>> returns its argument <[ch]>.  If an error
@@ -67,6 +100,8 @@ query for errors.
 PORTABILITY
 <<fputc>> is required by ANSI C.
 
+<<fputc_unlocked>> is a BSD extension also provided by GNU libc.
+
 Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
 <<lseek>>, <<read>>, <<sbrk>>, <<write>>.
 */
Index: libc/stdio/fputc_u.c
===================================================================
RCS file: libc/stdio/fputc_u.c
diff -N libc/stdio/fputc_u.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ libc/stdio/fputc_u.c	17 Dec 2014 18:27:03 -0000
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2014 Red Hat, Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <_ansi.h>
+#include <stdio.h>
+#include "local.h"
+
+int
+_DEFUN(_fputc_unlocked_r, (ptr, ch, file),
+       struct _reent *ptr _AND
+       int ch _AND
+       FILE * file)
+{
+  CHECK_INIT(ptr, file);
+  return _putc_unlocked_r (ptr, ch, file);
+}
+
+#ifndef _REENT_ONLY
+int
+_DEFUN(fputc_unlocked, (ch, file),
+       int ch _AND
+       FILE * file)
+{
+#if !defined(__OPTIMIZE_SIZE__) && !defined(PREFER_SIZE_OVER_SPEED)
+  struct _reent *reent = _REENT;
+
+  CHECK_INIT(reent, file);
+  return _putc_unlocked_r (reent, ch, file);
+#else
+  return _fputc_unlocked_r (_REENT, ch, file);
+#endif
+}
+#endif /* !_REENT_ONLY */