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1 | .\" Copyright (C) 1993 David Metcalfe (david@prism.demon.co.uk) |
2 | .\" | |
93015253 | 3 | .\" %%%LICENSE_START(VERBATIM) |
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4 | .\" Permission is granted to make and distribute verbatim copies of this |
5 | .\" manual provided the copyright notice and this permission notice are | |
6 | .\" preserved on all copies. | |
7 | .\" | |
8 | .\" Permission is granted to copy and distribute modified versions of this | |
9 | .\" manual under the conditions for verbatim copying, provided that the | |
10 | .\" entire resulting derived work is distributed under the terms of a | |
11 | .\" permission notice identical to this one. | |
c13182ef | 12 | .\" |
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13 | .\" Since the Linux kernel and libraries are constantly changing, this |
14 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
15 | .\" responsibility for errors or omissions, or for damages resulting from | |
16 | .\" the use of the information contained herein. The author(s) may not | |
17 | .\" have taken the same level of care in the production of this manual, | |
18 | .\" which is licensed free of charge, as they might when working | |
19 | .\" professionally. | |
c13182ef | 20 | .\" |
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21 | .\" Formatted or processed versions of this manual, if unaccompanied by |
22 | .\" the source, must acknowledge the copyright and authors of this work. | |
4b72fb64 | 23 | .\" %%%LICENSE_END |
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24 | .\" |
25 | .\" References consulted: | |
26 | .\" Linux libc source code | |
27 | .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) | |
28 | .\" 386BSD man pages | |
29 | .\" Modified Sat Jul 24 18:48:06 1993 by Rik Faith (faith@cs.unc.edu) | |
30 | .\" Modified Fri Jun 23 01:26:34 1995 by Andries Brouwer (aeb@cwi.nl) | |
31 | .\" (prompted by Scott Burkett <scottb@IntNet.net>) | |
32 | .\" Modified Sun Mar 28 23:44:38 1999 by Andries Brouwer (aeb@cwi.nl) | |
33 | .\" | |
4b8c67d9 | 34 | .TH MKTEMP 3 2017-09-15 "GNU" "Linux Programmer's Manual" |
fea681da | 35 | .SH NAME |
2c5f1089 | 36 | mktemp \- make a unique temporary filename |
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37 | .SH SYNOPSIS |
38 | .nf | |
39 | .B #include <stdlib.h> | |
68e4db0a | 40 | .PP |
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41 | .BI "char *mktemp(char *" template ); |
42 | .fi | |
68e4db0a | 43 | .PP |
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44 | .in -4n |
45 | Feature Test Macro Requirements for glibc (see | |
46 | .BR feature_test_macros (7)): | |
47 | .in | |
68e4db0a | 48 | .PP |
cc4615cc | 49 | .BR mktemp (): |
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50 | .ad l |
51 | .PD 0 | |
1348fbcb | 52 | .RS 4 |
f660f936 | 53 | .TP 4 |
77ea385c | 54 | Since glibc 2.12: |
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55 | (_XOPEN_SOURCE\ >=\ 500) && ! (_POSIX_C_SOURCE\ >=\ 200112L) |
56 | || /* Glibc since 2.19: */ _DEFAULT_SOURCE | |
57 | || /* Glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE | |
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58 | .TP |
59 | Before glibc 2.12: | |
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60 | _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 500 |
61 | .\" || _XOPEN_SOURCE\ &&\ _XOPEN_SOURCE_EXTENDED | |
b23c187c | 62 | .RE |
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63 | .PD |
64 | .ad b | |
fea681da | 65 | .SH DESCRIPTION |
3fd22afa | 66 | .IR "Never use this function" ; |
fcf4536c | 67 | see BUGS. |
847e0d88 | 68 | .PP |
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69 | The |
70 | .BR mktemp () | |
71 | function generates a unique temporary filename | |
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72 | from \fItemplate\fP. |
73 | The last six characters of \fItemplate\fP must | |
fea681da | 74 | be XXXXXX and these are replaced with a string that makes the |
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75 | filename unique. |
76 | Since it will be modified, | |
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77 | .I template |
78 | must not be a string constant, but should be declared as a character array. | |
47297adb | 79 | .SH RETURN VALUE |
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80 | The |
81 | .BR mktemp () | |
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82 | function always returns \fItemplate\fP. |
83 | If a unique name was created, the last six bytes of \fItemplate\fP will | |
fea681da | 84 | have been modified in such a way that the resulting name is unique |
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85 | (i.e., does not exist already) |
86 | If a unique name could not be created, | |
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87 | \fItemplate\fP is made an empty string, and |
88 | .I errno | |
89 | is set to indicate the error. | |
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90 | .SH ERRORS |
91 | .TP | |
92 | .B EINVAL | |
93 | The last six characters of \fItemplate\fP were not XXXXXX. | |
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94 | .SH ATTRIBUTES |
95 | For an explanation of the terms used in this section, see | |
96 | .BR attributes (7). | |
97 | .TS | |
98 | allbox; | |
99 | lb lb lb | |
100 | l l l. | |
101 | Interface Attribute Value | |
102 | T{ | |
103 | .BR mktemp () | |
104 | T} Thread safety MT-Safe | |
105 | .TE | |
47297adb | 106 | .SH CONFORMING TO |
fa5e7dd9 | 107 | 4.3BSD, POSIX.1-2001. |
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108 | POSIX.1-2008 removes the specification of |
109 | .BR mktemp (). | |
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110 | .\" .SH NOTES |
111 | .\" The prototype is in | |
112 | .\" .I <unistd.h> | |
113 | .\" for libc4, libc5, glibc1; glibc2 follows the Single UNIX Specification | |
114 | .\" and has the prototype in | |
115 | .\" .IR <stdlib.h> . | |
fea681da | 116 | .SH BUGS |
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117 | Never use |
118 | .BR mktemp (). | |
c13182ef | 119 | Some implementations follow 4.3BSD |
357cf3fe | 120 | and replace XXXXXX by the current process ID and a single letter, |
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121 | so that at most 26 different names can be returned. |
122 | Since on the one hand the names are easy to guess, and on the other | |
123 | hand there is a race between testing whether the name exists and | |
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124 | opening the file, every use of |
125 | .BR mktemp () | |
126 | is a security risk. | |
fea681da | 127 | The race is avoided by |
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128 | .BR mkstemp (3) |
129 | and | |
9b44ad20 | 130 | .BR mkdtemp (3). |
47297adb | 131 | .SH SEE ALSO |
c39946e0 | 132 | .BR mktemp (1), |
9b44ad20 | 133 | .BR mkdtemp (3), |
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134 | .BR mkstemp (3), |
135 | .BR tempnam (3), | |
136 | .BR tmpfile (3), | |
137 | .BR tmpnam (3) |