Sat Sep 11 19:05:06 2021 UTC ()
stdio.h: sync comment for struct __sFILE with reality

In stdio.h 1.1 from 1993-03-21, the struct had a member named _ub for
the ungetc buffer.  That member was repurposed in stdio.h 1.42 from
2001-12-07 in order to support wide characters.

Remove the reference to the 'WARNING above' since there is no such
warning and even when this comment was added in stdio.h 1.20 from
1998-02-02, there was none.


(rillig)
diff -r1.102 -r1.103 src/include/stdio.h
cvs diff -r1.102 -r1.103 src/include/stdio.h (expand / switch to unified diff)

--- src/include/stdio.h 2021/09/11 18:38:25 1.102
+++ src/include/stdio.h 2021/09/11 19:05:06 1.103
@@ -1,14 +1,14 @@ @@ -1,14 +1,14 @@
1/* $NetBSD: stdio.h,v 1.102 2021/09/11 18:38:25 rillig Exp $ */ 1/* $NetBSD: stdio.h,v 1.103 2021/09/11 19:05:06 rillig Exp $ */
2 2
3/*- 3/*-
4 * Copyright (c) 1990, 1993 4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved. 5 * The Regents of the University of California. All rights reserved.
6 * 6 *
7 * This code is derived from software contributed to Berkeley by 7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek. 8 * Chris Torek.
9 * 9 *
10 * Redistribution and use in source and binary forms, with or without 10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions 11 * modification, are permitted provided that the following conditions
12 * are met: 12 * are met:
13 * 1. Redistributions of source code must retain the above copyright 13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer. 14 * notice, this list of conditions and the following disclaimer.
@@ -93,33 +93,32 @@ struct __sbuf { @@ -93,33 +93,32 @@ struct __sbuf {
93 * if (_flags&(__SLBF|__SWR)) == (__SLBF|__SWR), 93 * if (_flags&(__SLBF|__SWR)) == (__SLBF|__SWR),
94 * _lbfsize is -_bf._size, else _lbfsize is 0 94 * _lbfsize is -_bf._size, else _lbfsize is 0
95 * if _flags&__SRD, _w is 0 95 * if _flags&__SRD, _w is 0
96 * if _flags&__SWR, _r is 0 96 * if _flags&__SWR, _r is 0
97 * 97 *
98 * This ensures that the getc and putc macros (or inline functions) never 98 * This ensures that the getc and putc macros (or inline functions) never
99 * try to write or read from a file that is in `read' or `write' mode. 99 * try to write or read from a file that is in `read' or `write' mode.
100 * (Moreover, they can, and do, automatically switch from read mode to 100 * (Moreover, they can, and do, automatically switch from read mode to
101 * write mode, and back, on "r+" and "w+" files.) 101 * write mode, and back, on "r+" and "w+" files.)
102 * 102 *
103 * _lbfsize is used only to make the inline line-buffered output stream 103 * _lbfsize is used only to make the inline line-buffered output stream
104 * code as compact as possible. 104 * code as compact as possible.
105 * 105 *
106 * _ub, _up, and _ur are used when ungetc() pushes back more characters 106 * _ub (via _ext and struct __sfileext), _up, and _ur are used when ungetc()
107 * than fit in the current _bf, or when ungetc() pushes back a character 107 * pushes back more characters than fit in the current _bf, or when ungetc()
108 * that does not match the previous one in _bf. When this happens, 108 * pushes back a character that does not match the previous one in _bf.
109 * _ub._base becomes non-nil (i.e., a stream has ungetc() data iff 109 * When this happens, _ext._base becomes non-nil (i.e., a stream has ungetc()
110 * _ub._base!=NULL) and _up and _ur save the current values of _p and _r. 110 * data iff _ub._base != NULL) and _up and _ur save the current values of _p
111 * 111 * and _r.
112 * NB: see WARNING above before changing the layout of this structure! 
113 */ 112 */
114typedef struct __sFILE { 113typedef struct __sFILE {
115 unsigned char *_p; /* current position in (some) buffer */ 114 unsigned char *_p; /* current position in (some) buffer */
116 int _r; /* read space left for getc() */ 115 int _r; /* read space left for getc() */
117 int _w; /* write space left for putc() */ 116 int _w; /* write space left for putc() */
118 unsigned short _flags; /* flags, below; this FILE is free if 0 */ 117 unsigned short _flags; /* flags, below; this FILE is free if 0 */
119 short _file; /* fileno, if Unix descriptor, else -1 */ 118 short _file; /* fileno, if Unix descriptor, else -1 */
120 struct __sbuf _bf; /* the buffer (at least 1 byte, if !NULL) */ 119 struct __sbuf _bf; /* the buffer (at least 1 byte, if !NULL) */
121 int _lbfsize; /* 0 or -_bf._size, for inline putc */ 120 int _lbfsize; /* 0 or -_bf._size, for inline putc */
122 121
123 /* operations */ 122 /* operations */
124 void *_cookie; /* cookie passed to io functions */ 123 void *_cookie; /* cookie passed to io functions */
125 int (*_close)(void *); 124 int (*_close)(void *);