1MKTEMP(3)                  Linux Programmer's Manual                 MKTEMP(3)
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NAME

6       mktemp - make a unique temporary filename
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SYNOPSIS

9       #include <stdlib.h>
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11       char *mktemp(char *template);
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13   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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15       mktemp():
16           Since glibc 2.12:
17               _BSD_SOURCE || _SVID_SOURCE ||
18                   (_XOPEN_SOURCE >= 500 ||
19                        _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED) &&
20                   !(_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)
21           Before glibc 2.12:
22               _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
23               _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
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DESCRIPTION

26       The mktemp() function generates a unique temporary filename  from  tem‐
27       plate.   The  last  six characters of template must be XXXXXX and these
28       are replaced with a string that makes the filename  unique.   Since  it
29       will be modified, template must not be a string constant, but should be
30       declared as a character array.
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RETURN VALUE

33       The mktemp() function always returns template.  If a  unique  name  was
34       created, the last six bytes of template will have been modified in such
35       a way that the resulting name is unique (i.e., does not exist  already)
36       If  a  unique  name  could  not  be  created, template is made an empty
37       string, and errno is set to indicate the error.
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ERRORS

40       EINVAL The last six characters of template were not XXXXXX.
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CONFORMING TO

43       4.3BSD,  POSIX.1-2001.   POSIX.1-2008  removes  the  specification   of
44       mktemp().
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NOTES

47       The prototype is in <unistd.h> for libc4, libc5, glibc1; glibc2 follows
48       the Single UNIX Specification and has the prototype in <stdlib.h>.
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BUGS

51       Never use mktemp().  Some implementations  follow  4.3BSD  and  replace
52       XXXXXX  by  the current process ID and a single letter, so that at most
53       26 different names can be returned.  Since on the one  hand  the  names
54       are  easy to guess, and on the other hand there is a race between test‐
55       ing whether the name exists and opening the file, every use of mktemp()
56       is a security risk.  The race is avoided by mkstemp(3).
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SEE ALSO

59       mkstemp(3), tempnam(3), tmpfile(3), tmpnam(3)
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COLOPHON

62       This  page  is  part of release 3.53 of the Linux man-pages project.  A
63       description of the project, and information about reporting  bugs,  can
64       be found at http://www.kernel.org/doc/man-pages/.
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68GNU                               2013-04-19                         MKTEMP(3)
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