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| Rev | Author | Line No. | Line |
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| 2 | pj | 1 | /*- |
| 2 | * Copyright (c) 1990, 1993 |
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| 3 | * The Regents of the University of California. All rights reserved. |
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| 4 | * |
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| 5 | * This code is derived from software contributed to Berkeley by |
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| 6 | * Chris Torek. |
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| 7 | * |
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| 8 | * Redistribution and use in source and binary forms, with or without |
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| 9 | * modification, are permitted provided that the following conditions |
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| 10 | * are met: |
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| 11 | * 1. Redistributions of source code must retain the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer. |
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| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
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| 14 | * notice, this list of conditions and the following disclaimer in the |
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| 15 | * documentation and/or other materials provided with the distribution. |
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| 16 | * 3. All advertising materials mentioning features or use of this software |
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| 17 | * must display the following acknowledgement: |
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| 18 | * This product includes software developed by the University of |
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| 19 | * California, Berkeley and its contributors. |
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| 20 | * 4. Neither the name of the University nor the names of its contributors |
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| 21 | * may be used to endorse or promote products derived from this software |
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| 22 | * without specific prior written permission. |
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| 23 | * |
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| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
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| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
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| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
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| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
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| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
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| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
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| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
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| 34 | * SUCH DAMAGE. |
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| 35 | */ |
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| 36 | |||
| 37 | #if defined(LIBC_SCCS) && !defined(lint) |
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| 38 | #if 0 |
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| 39 | static char sccsid[] = "@(#)ungetc.c 8.2 (Berkeley) 11/3/93"; |
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| 40 | #endif |
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| 41 | static const char rcsid[] = |
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| 42 | "$\Id: ungetc.c,v 1.3 1996/06/22 10:33:59 jraynard Exp $"; |
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| 43 | #endif /* LIBC_SCCS and not lint */ |
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| 44 | |||
| 45 | #include <stdio.h> |
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| 46 | #include <stdlib.h> |
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| 47 | #include <string.h> |
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| 48 | #include "local.h" |
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| 49 | #ifdef _THREAD_SAFE |
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| 50 | #include <pthread.h> |
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| 51 | #include "pthread_private.h" |
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| 52 | #endif |
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| 53 | |||
| 54 | static int __submore __P((FILE *)); |
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| 55 | |||
| 56 | /* |
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| 57 | * Expand the ungetc buffer `in place'. That is, adjust fp->_p when |
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| 58 | * the buffer moves, so that it points the same distance from the end, |
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| 59 | * and move the bytes in the buffer around as necessary so that they |
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| 60 | * are all at the end (stack-style). |
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| 61 | */ |
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| 62 | static int |
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| 63 | __submore(fp) |
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| 64 | register FILE *fp; |
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| 65 | { |
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| 66 | register int i; |
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| 67 | register unsigned char *p; |
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| 68 | |||
| 69 | if (fp->_ub._base == fp->_ubuf) { |
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| 70 | /* |
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| 71 | * Get a new buffer (rather than expanding the old one). |
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| 72 | */ |
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| 73 | if ((p = malloc((size_t)BUFSIZ)) == NULL) |
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| 74 | return (EOF); |
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| 75 | fp->_ub._base = p; |
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| 76 | fp->_ub._size = BUFSIZ; |
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| 77 | p += BUFSIZ - sizeof(fp->_ubuf); |
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| 78 | for (i = sizeof(fp->_ubuf); --i >= 0;) |
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| 79 | p[i] = fp->_ubuf[i]; |
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| 80 | fp->_p = p; |
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| 81 | return (0); |
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| 82 | } |
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| 83 | i = fp->_ub._size; |
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| 84 | p = realloc(fp->_ub._base, (size_t)(i << 1)); |
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| 85 | if (p == NULL) |
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| 86 | return (EOF); |
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| 87 | /* no overlap (hence can use memcpy) because we doubled the size */ |
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| 88 | (void)memcpy((void *)(p + i), (void *)p, (size_t)i); |
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| 89 | fp->_p = p + i; |
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| 90 | fp->_ub._base = p; |
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| 91 | fp->_ub._size = i << 1; |
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| 92 | return (0); |
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| 93 | } |
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| 94 | |||
| 95 | int |
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| 96 | ungetc(c, fp) |
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| 97 | int c; |
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| 98 | register FILE *fp; |
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| 99 | { |
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| 100 | if (c == EOF) |
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| 101 | return (EOF); |
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| 102 | if (!__sdidinit) |
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| 103 | __sinit(); |
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| 104 | #ifdef _THREAD_SAFE |
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| 105 | _thread_flockfile(fp,__FILE__,__LINE__); |
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| 106 | #endif |
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| 107 | if ((fp->_flags & __SRD) == 0) { |
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| 108 | /* |
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| 109 | * Not already reading: no good unless reading-and-writing. |
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| 110 | * Otherwise, flush any current write stuff. |
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| 111 | */ |
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| 112 | if ((fp->_flags & __SRW) == 0) { |
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| 113 | #ifdef _THREAD_SAFE |
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| 114 | _thread_funlockfile(fp); |
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| 115 | #endif |
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| 116 | return (EOF); |
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| 117 | } |
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| 118 | if (fp->_flags & __SWR) { |
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| 119 | if (__sflush(fp)) { |
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| 120 | #ifdef _THREAD_SAFE |
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| 121 | _thread_funlockfile(fp); |
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| 122 | #endif |
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| 123 | return (EOF); |
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| 124 | } |
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| 125 | fp->_flags &= ~__SWR; |
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| 126 | fp->_w = 0; |
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| 127 | fp->_lbfsize = 0; |
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| 128 | } |
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| 129 | fp->_flags |= __SRD; |
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| 130 | } |
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| 131 | c = (unsigned char)c; |
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| 132 | |||
| 133 | /* |
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| 134 | * If we are in the middle of ungetc'ing, just continue. |
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| 135 | * This may require expanding the current ungetc buffer. |
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| 136 | */ |
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| 137 | if (HASUB(fp)) { |
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| 138 | if (fp->_r >= fp->_ub._size && __submore(fp)) { |
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| 139 | #ifdef _THREAD_SAFE |
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| 140 | _thread_funlockfile(fp); |
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| 141 | #endif |
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| 142 | return (EOF); |
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| 143 | } |
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| 144 | *--fp->_p = c; |
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| 145 | fp->_r++; |
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| 146 | #ifdef _THREAD_SAFE |
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| 147 | _thread_funlockfile(fp); |
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| 148 | #endif |
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| 149 | return (c); |
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| 150 | } |
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| 151 | fp->_flags &= ~__SEOF; |
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| 152 | |||
| 153 | /* |
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| 154 | * If we can handle this by simply backing up, do so, |
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| 155 | * but never replace the original character. |
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| 156 | * (This makes sscanf() work when scanning `const' data.) |
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| 157 | */ |
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| 158 | if (fp->_bf._base != NULL && fp->_p > fp->_bf._base && |
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| 159 | fp->_p[-1] == c) { |
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| 160 | fp->_p--; |
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| 161 | fp->_r++; |
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| 162 | #ifdef _THREAD_SAFE |
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| 163 | _thread_funlockfile(fp); |
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| 164 | #endif |
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| 165 | return (c); |
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| 166 | } |
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| 167 | |||
| 168 | /* |
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| 169 | * Create an ungetc buffer. |
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| 170 | * Initially, we will use the `reserve' buffer. |
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| 171 | */ |
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| 172 | fp->_ur = fp->_r; |
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| 173 | fp->_up = fp->_p; |
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| 174 | fp->_ub._base = fp->_ubuf; |
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| 175 | fp->_ub._size = sizeof(fp->_ubuf); |
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| 176 | fp->_ubuf[sizeof(fp->_ubuf) - 1] = c; |
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| 177 | fp->_p = &fp->_ubuf[sizeof(fp->_ubuf) - 1]; |
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| 178 | fp->_r = 1; |
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| 179 | #ifdef _THREAD_SAFE |
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| 180 | _thread_funlockfile(fp); |
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| 181 | #endif |
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| 182 | return (c); |
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| 183 | } |