[444] | 1 | /* |
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| 2 | * Copyright (c) 1990 The Regents of the University of California. |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms are permitted |
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| 6 | * provided that the above copyright notice and this paragraph are |
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| 7 | * duplicated in all such forms and that any documentation, |
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| 8 | * advertising materials, and other materials related to such |
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| 9 | * distribution and use acknowledge that the software was developed |
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| 10 | * by the University of California, Berkeley. The name of the |
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| 11 | * University may not be used to endorse or promote products derived |
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| 12 | * from this software without specific prior written permission. |
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| 13 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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| 14 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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| 15 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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| 16 | */ |
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| 17 | |
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| 18 | /* |
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| 19 | FUNCTION |
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| 20 | <<fgets>>, <<fgets_unlocked>>---get character string from a file or stream |
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| 21 | |
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| 22 | INDEX |
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| 23 | fgets |
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| 24 | INDEX |
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| 25 | fgets_unlocked |
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| 26 | INDEX |
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| 27 | _fgets_r |
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| 28 | INDEX |
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| 29 | _fgets_unlocked_r |
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| 30 | |
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| 31 | SYNOPSIS |
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| 32 | #include <stdio.h> |
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| 33 | char *fgets(char *restrict <[buf]>, int <[n]>, FILE *restrict <[fp]>); |
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| 34 | |
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| 35 | #define _GNU_SOURCE |
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| 36 | #include <stdio.h> |
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| 37 | char *fgets_unlocked(char *restrict <[buf]>, int <[n]>, FILE *restrict <[fp]>); |
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| 38 | |
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| 39 | #include <stdio.h> |
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| 40 | char *_fgets_r(struct _reent *<[ptr]>, char *restrict <[buf]>, int <[n]>, FILE *restrict <[fp]>); |
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| 41 | |
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| 42 | #include <stdio.h> |
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| 43 | char *_fgets_unlocked_r(struct _reent *<[ptr]>, char *restrict <[buf]>, int <[n]>, FILE *restrict <[fp]>); |
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| 44 | |
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| 45 | DESCRIPTION |
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| 46 | Reads at most <[n-1]> characters from <[fp]> until a newline |
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| 47 | is found. The characters including to the newline are stored |
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| 48 | in <[buf]>. The buffer is terminated with a 0. |
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| 49 | |
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| 50 | <<fgets_unlocked>> is a non-thread-safe version of <<fgets>>. |
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| 51 | <<fgets_unlocked>> may only safely be used within a scope |
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| 52 | protected by flockfile() (or ftrylockfile()) and funlockfile(). This |
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| 53 | function may safely be used in a multi-threaded program if and only |
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| 54 | if they are called while the invoking thread owns the (FILE *) |
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| 55 | object, as is the case after a successful call to the flockfile() or |
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| 56 | ftrylockfile() functions. If threads are disabled, then |
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| 57 | <<fgets_unlocked>> is equivalent to <<fgets>>. |
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| 58 | |
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| 59 | The functions <<_fgets_r>> and <<_fgets_unlocked_r>> are simply |
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| 60 | reentrant versions that are passed the additional reentrant structure |
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| 61 | pointer argument: <[ptr]>. |
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| 62 | |
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| 63 | RETURNS |
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| 64 | <<fgets>> returns the buffer passed to it, with the data |
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| 65 | filled in. If end of file occurs with some data already |
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| 66 | accumulated, the data is returned with no other indication. If |
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| 67 | no data are read, NULL is returned instead. |
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| 68 | |
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| 69 | PORTABILITY |
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| 70 | <<fgets>> should replace all uses of <<gets>>. Note however |
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| 71 | that <<fgets>> returns all of the data, while <<gets>> removes |
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| 72 | the trailing newline (with no indication that it has done so.) |
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| 73 | |
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| 74 | <<fgets_unlocked>> is a GNU extension. |
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| 75 | |
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| 76 | Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>, |
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| 77 | <<lseek>>, <<read>>, <<sbrk>>, <<write>>. |
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| 78 | */ |
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| 79 | |
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| 80 | #include <_ansi.h> |
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| 81 | #include <stdio.h> |
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| 82 | #include <string.h> |
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| 83 | #include "local.h" |
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| 84 | |
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| 85 | #ifdef __IMPL_UNLOCKED__ |
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| 86 | #define _fgets_r _fgets_unlocked_r |
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| 87 | #define fgets fgets_unlocked |
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| 88 | #endif |
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| 89 | |
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| 90 | /* |
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| 91 | * Read at most n-1 characters from the given file. |
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| 92 | * Stop when a newline has been read, or the count runs out. |
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| 93 | * Return first argument, or NULL if no characters were read. |
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| 94 | */ |
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| 95 | |
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| 96 | char * |
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| 97 | _fgets_r (struct _reent * ptr, |
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| 98 | char *__restrict buf, |
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| 99 | int n, |
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| 100 | FILE *__restrict fp) |
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| 101 | { |
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| 102 | size_t len; |
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| 103 | char *s; |
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| 104 | unsigned char *p, *t; |
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| 105 | |
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| 106 | if (n < 2) /* sanity check */ |
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| 107 | return 0; |
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| 108 | |
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| 109 | s = buf; |
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| 110 | |
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| 111 | CHECK_INIT(ptr, fp); |
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| 112 | |
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| 113 | _newlib_flockfile_start (fp); |
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| 114 | #ifdef __SCLE |
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| 115 | if (fp->_flags & __SCLE) |
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| 116 | { |
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| 117 | int c = 0; |
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| 118 | /* Sorry, have to do it the slow way */ |
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| 119 | while (--n > 0 && (c = __sgetc_r (ptr, fp)) != EOF) |
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| 120 | { |
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| 121 | *s++ = c; |
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| 122 | if (c == '\n') |
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| 123 | break; |
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| 124 | } |
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| 125 | if (c == EOF && s == buf) |
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| 126 | { |
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| 127 | _newlib_flockfile_exit (fp); |
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| 128 | return NULL; |
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| 129 | } |
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| 130 | *s = 0; |
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| 131 | _newlib_flockfile_exit (fp); |
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| 132 | return buf; |
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| 133 | } |
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| 134 | #endif |
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| 135 | |
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| 136 | n--; /* leave space for NUL */ |
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| 137 | do |
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| 138 | { |
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| 139 | /* |
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| 140 | * If the buffer is empty, refill it. |
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| 141 | */ |
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| 142 | if ((len = fp->_r) <= 0) |
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| 143 | { |
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| 144 | if (__srefill_r (ptr, fp)) |
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| 145 | { |
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| 146 | /* EOF: stop with partial or no line */ |
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| 147 | if (s == buf) |
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| 148 | { |
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| 149 | _newlib_flockfile_exit (fp); |
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| 150 | return 0; |
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| 151 | } |
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| 152 | break; |
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| 153 | } |
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| 154 | len = fp->_r; |
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| 155 | } |
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| 156 | p = fp->_p; |
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| 157 | |
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| 158 | /* |
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| 159 | * Scan through at most n bytes of the current buffer, |
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| 160 | * looking for '\n'. If found, copy up to and including |
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| 161 | * newline, and stop. Otherwise, copy entire chunk |
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| 162 | * and loop. |
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| 163 | */ |
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| 164 | if (len > n) |
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| 165 | len = n; |
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| 166 | t = (unsigned char *) memchr ((void *) p, '\n', len); |
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| 167 | if (t != 0) |
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| 168 | { |
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| 169 | len = ++t - p; |
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| 170 | fp->_r -= len; |
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| 171 | fp->_p = t; |
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| 172 | (void) memcpy ((void *) s, (void *) p, len); |
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| 173 | s[len] = 0; |
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| 174 | _newlib_flockfile_exit (fp); |
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| 175 | return (buf); |
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| 176 | } |
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| 177 | fp->_r -= len; |
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| 178 | fp->_p += len; |
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| 179 | (void) memcpy ((void *) s, (void *) p, len); |
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| 180 | s += len; |
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| 181 | } |
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| 182 | while ((n -= len) != 0); |
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| 183 | *s = 0; |
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| 184 | _newlib_flockfile_end (fp); |
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| 185 | return buf; |
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| 186 | } |
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| 187 | |
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| 188 | #ifndef _REENT_ONLY |
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| 189 | |
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| 190 | char * |
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| 191 | fgets (char *__restrict buf, |
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| 192 | int n, |
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| 193 | FILE *__restrict fp) |
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| 194 | { |
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| 195 | return _fgets_r (_REENT, buf, n, fp); |
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| 196 | } |
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| 197 | |
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| 198 | #endif /* !_REENT_ONLY */ |
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