1 .\" Copyright (c) 1999 Andries Brouwer (aeb@cwi.nl)
3 .\" %%%LICENSE_START(VERBATIM)
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25 .\" 2003-11-15, aeb, added tmpnam_r
27 .TH TMPNAM 3 2010-09-10 "" "Linux Programmer's Manual"
29 tmpnam, tmpnam_r \- create a name for a temporary file
34 .BI "char *tmpnam(char *" s );
39 function returns a pointer to a string that is a valid filename,
40 and such that a file with this name did not exist at some point
41 in time, so that naive programmers may think it
42 a suitable name for a temporary file.
45 is NULL this name is generated in an internal static buffer
46 and may be overwritten by the next call to
50 is not NULL, the name is copied to the character array (of length
57 is returned in case of success.
59 The pathname that is created, has a directory prefix
73 function returns a pointer to a unique temporary
74 filename, or NULL if a unique name cannot be generated.
76 No errors are defined.
78 SVr4, 4.3BSD, C89, C99, POSIX.1-2001.
85 function generates a different string each time it is called,
89 If it is called more than
92 the behavior is implementation defined.
96 generates names that are difficult to guess,
97 it is nevertheless possible that between the time that
99 returns a pathname, and the time that the program opens it,
100 another program might create that pathname using
102 or create it as a symbolic link.
103 This can lead to security holes.
104 To avoid such possibilities, use the
107 flag to open the pathname.
113 Portable applications that use threads cannot call
115 with a NULL argument if either
118 .B _POSIX_THREAD_SAFE_FUNCTIONS
121 A POSIX draft proposed to use a function
130 return s ? tmpnam(s) : NULL;
135 apparently as a warning not to use NULL.
136 A few systems implement it.
137 To get a glibc prototype for this function from
147 Never use this function.