1 .\" Copyright (c) 1999 Andries Brouwer (aeb@cwi.nl)
3 .\" %%%LICENSE_START(VERBATIM)
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13 .\" Since the Linux kernel and libraries are constantly changing, this
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25 .\" 2003-11-15, aeb, added tmpnam_r
27 .TH TMPNAM 3 2017-09-15 "" "Linux Programmer's Manual"
29 tmpnam, tmpnam_r \- create a name for a temporary file
34 .BI "char *tmpnam(char *" s );
35 .BI "char *tmpnam_r(char *" s );
39 Feature Test Macro Requirements for glibc (see
40 .BR feature_test_macros (7)):
51 Up to and including glibc 2.19:
52 _BSD_SOURCE || _SVID_SOURCE
58 avoid using these functions; use
66 function returns a pointer to a string that is a valid filename,
67 and such that a file with this name did not exist at some point
68 in time, so that naive programmers may think it
69 a suitable name for a temporary file.
72 is NULL, this name is generated in an internal static buffer
73 and may be overwritten by the next call to
77 is not NULL, the name is copied to the character array (of length
84 is returned in case of success.
86 The created pathname has a directory prefix
100 function performs the same task as
102 but returns NULL (to indicate an error) if
106 These functions return a pointer to a unique temporary
107 filename, or NULL if a unique name cannot be generated.
109 No errors are defined.
111 For an explanation of the terms used in this section, see
117 Interface Attribute Value
120 T} Thread safety MT-Unsafe race:tmpnam/!s
123 T} Thread safety MT-Safe
127 SVr4, 4.3BSD, C89, C99, POSIX.1-2001.
133 is a nonstandard extension that is also available
134 .\" Appears to be on Solaris
135 on a few other systems.
139 function generates a different string each time it is called,
143 If it is called more than
146 the behavior is implementation defined.
148 Although these functions generate names that are difficult to guess,
149 it is nevertheless possible that between the time that
150 the pathname is returned and the time that the program opens it,
151 another program might create that pathname using
153 or create it as a symbolic link.
154 This can lead to security holes.
155 To avoid such possibilities, use the
158 flag to open the pathname.
164 Portable applications that use threads cannot call
166 with a NULL argument if either
169 .B _POSIX_THREAD_SAFE_FUNCTIONS
172 Never use these functions.