[444] | 1 | /* |
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| 2 | * tmpname.c |
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| 3 | * Original Author: G. Haley |
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| 4 | */ |
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| 5 | /* |
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| 6 | FUNCTION |
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| 7 | <<tmpnam>>, <<tempnam>>---name for a temporary file |
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| 8 | |
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| 9 | INDEX |
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| 10 | tmpnam |
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| 11 | INDEX |
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| 12 | tempnam |
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| 13 | INDEX |
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| 14 | _tmpnam_r |
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| 15 | INDEX |
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| 16 | _tempnam_r |
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| 17 | |
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| 18 | SYNOPSIS |
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| 19 | #include <stdio.h> |
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| 20 | char *tmpnam(char *<[s]>); |
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| 21 | char *tempnam(char *<[dir]>, char *<[pfx]>); |
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| 22 | char *_tmpnam_r(struct _reent *<[reent]>, char *<[s]>); |
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| 23 | char *_tempnam_r(struct _reent *<[reent]>, char *<[dir]>, char *<[pfx]>); |
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| 24 | |
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| 25 | DESCRIPTION |
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| 26 | Use either of these functions to generate a name for a temporary file. |
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| 27 | The generated name is guaranteed to avoid collision with other files |
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| 28 | (for up to <<TMP_MAX>> calls of either function). |
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| 29 | |
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| 30 | <<tmpnam>> generates file names with the value of <<P_tmpdir>> |
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| 31 | (defined in `<<stdio.h>>') as the leading directory component of the path. |
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| 32 | |
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| 33 | You can use the <<tmpnam>> argument <[s]> to specify a suitable area |
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| 34 | of memory for the generated filename; otherwise, you can call |
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| 35 | <<tmpnam(NULL)>> to use an internal static buffer. |
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| 36 | |
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| 37 | <<tempnam>> allows you more control over the generated filename: you |
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| 38 | can use the argument <[dir]> to specify the path to a directory for |
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| 39 | temporary files, and you can use the argument <[pfx]> to specify a |
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| 40 | prefix for the base filename. |
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| 41 | |
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| 42 | If <[dir]> is <<NULL>>, <<tempnam>> will attempt to use the value of |
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| 43 | environment variable <<TMPDIR>> instead; if there is no such value, |
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| 44 | <<tempnam>> uses the value of <<P_tmpdir>> (defined in `<<stdio.h>>'). |
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| 45 | |
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| 46 | If you don't need any particular prefix to the basename of temporary |
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| 47 | files, you can pass <<NULL>> as the <[pfx]> argument to <<tempnam>>. |
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| 48 | |
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| 49 | <<_tmpnam_r>> and <<_tempnam_r>> are reentrant versions of <<tmpnam>> |
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| 50 | and <<tempnam>> respectively. The extra argument <[reent]> is a |
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| 51 | pointer to a reentrancy structure. |
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| 52 | |
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| 53 | WARNINGS |
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| 54 | The generated filenames are suitable for temporary files, but do not |
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| 55 | in themselves make files temporary. Files with these names must still |
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| 56 | be explicitly removed when you no longer want them. |
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| 57 | |
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| 58 | If you supply your own data area <[s]> for <<tmpnam>>, you must ensure |
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| 59 | that it has room for at least <<L_tmpnam>> elements of type <<char>>. |
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| 60 | |
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| 61 | RETURNS |
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| 62 | Both <<tmpnam>> and <<tempnam>> return a pointer to the newly |
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| 63 | generated filename. |
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| 64 | |
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| 65 | PORTABILITY |
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| 66 | ANSI C requires <<tmpnam>>, but does not specify the use of |
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| 67 | <<P_tmpdir>>. The System V Interface Definition (Issue 2) requires |
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| 68 | both <<tmpnam>> and <<tempnam>>. |
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| 69 | |
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| 70 | Supporting OS subroutines required: <<close>>, <<fstat>>, <<getpid>>, |
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| 71 | <<isatty>>, <<lseek>>, <<open>>, <<read>>, <<sbrk>>, <<write>>. |
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| 72 | |
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| 73 | The global pointer <<environ>> is also required. |
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| 74 | */ |
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| 75 | |
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| 76 | #include <_ansi.h> |
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| 77 | #include <reent.h> |
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| 78 | #include <stdio.h> |
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| 79 | #include <stdlib.h> |
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| 80 | #include <string.h> |
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| 81 | #include <fcntl.h> |
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| 82 | #include <reent.h> |
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| 83 | #include <errno.h> |
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| 84 | |
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| 85 | /* Try to open the file specified, if it can't be opened then try |
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| 86 | another one. Return nonzero if successful, otherwise zero. */ |
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| 87 | |
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| 88 | static int |
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| 89 | worker (struct _reent *ptr, |
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| 90 | char *result, |
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| 91 | const char *part1, |
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| 92 | const char *part2, |
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| 93 | int part3, |
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| 94 | int *part4) |
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| 95 | { |
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| 96 | /* Generate the filename and make sure that there isn't one called |
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| 97 | it already. */ |
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| 98 | |
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| 99 | while (1) |
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| 100 | { |
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| 101 | int t; |
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| 102 | _sprintf_r (ptr, result, "%s/%s%x.%x", part1, part2, part3, *part4); |
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| 103 | (*part4)++; |
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| 104 | t = _open_r (ptr, result, O_RDONLY, 0); |
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| 105 | if (t == -1) |
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| 106 | { |
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| 107 | if (ptr->_errno == ENOSYS) |
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| 108 | { |
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| 109 | result[0] = '\0'; |
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| 110 | return 0; |
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| 111 | } |
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| 112 | break; |
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| 113 | } |
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| 114 | _close_r (ptr, t); |
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| 115 | } |
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| 116 | return 1; |
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| 117 | } |
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| 118 | |
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| 119 | char * |
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| 120 | _tmpnam_r (struct _reent *p, |
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| 121 | char *s) |
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| 122 | { |
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| 123 | char *result; |
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| 124 | int pid; |
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| 125 | |
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| 126 | if (s == NULL) |
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| 127 | { |
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| 128 | /* ANSI states we must use an internal static buffer if s is NULL */ |
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| 129 | _REENT_CHECK_EMERGENCY(p); |
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| 130 | result = _REENT_EMERGENCY(p); |
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| 131 | } |
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| 132 | else |
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| 133 | { |
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| 134 | result = s; |
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| 135 | } |
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| 136 | pid = _getpid_r (p); |
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| 137 | |
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| 138 | if (worker (p, result, P_tmpdir, "t", pid, &p->_inc)) |
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| 139 | { |
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| 140 | p->_inc++; |
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| 141 | return result; |
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| 142 | } |
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| 143 | |
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| 144 | return NULL; |
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| 145 | } |
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| 146 | |
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| 147 | char * |
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| 148 | _tempnam_r (struct _reent *p, |
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| 149 | const char *dir, |
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| 150 | const char *pfx) |
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| 151 | { |
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| 152 | char *filename; |
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| 153 | int length; |
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| 154 | const char *prefix = (pfx) ? pfx : ""; |
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| 155 | if (dir == NULL && (dir = getenv ("TMPDIR")) == NULL) |
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| 156 | dir = P_tmpdir; |
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| 157 | |
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| 158 | /* two 8 digit numbers + . / */ |
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| 159 | length = strlen (dir) + strlen (prefix) + (4 * sizeof (int)) + 2 + 1; |
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| 160 | |
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| 161 | filename = _malloc_r (p, length); |
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| 162 | if (filename) |
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| 163 | { |
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| 164 | if (! worker (p, filename, dir, prefix, |
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| 165 | _getpid_r (p) ^ (int) (_POINTER_INT) p, &p->_inc)) |
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| 166 | return NULL; |
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| 167 | } |
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| 168 | return filename; |
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| 169 | } |
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| 170 | |
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| 171 | #ifndef _REENT_ONLY |
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| 172 | |
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| 173 | char * |
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| 174 | tempnam (const char *dir, |
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| 175 | const char *pfx) |
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| 176 | { |
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| 177 | return _tempnam_r (_REENT, dir, pfx); |
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| 178 | } |
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| 179 | |
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| 180 | char * |
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| 181 | tmpnam (char *s) |
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| 182 | { |
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| 183 | return _tmpnam_r (_REENT, s); |
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| 184 | } |
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| 185 | |
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| 186 | #endif |
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