1TEMPNAM(3P) POSIX Programmer's Manual TEMPNAM(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 tempnam — create a name for a temporary file
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15 #include <stdio.h>
16 char *tempnam(const char *dir, const char *pfx);
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20 The tempnam() function shall generate a pathname that may be used for a
21 temporary file.
22 The tempnam() function allows the user to control the choice of a
24 directory. The dir argument points to the name of the directory in
25 which the file is to be created. If dir is a null pointer or points to
26 a string which is not a name for an appropriate directory, the path
27 prefix defined as P_tmpdir in the <stdio.h> header shall be used. If
28 that directory is not accessible, an implementation-defined directory
29 may be used.
30 Many applications prefer their temporary files to have certain initial
32 letter sequences in their names. The pfx argument should be used for
33 this. This argument may be a null pointer or point to a string of up to
34 five bytes to be used as the beginning of the filename.
35 Some implementations of tempnam() may use tmpnam() internally. On such
37 implementations, if called more than {TMP_MAX} times in a single
38 process, the behavior is implementation-defined.
39
41 Upon successful completion, tempnam() shall allocate space for a
42 string, put the generated pathname in that space, and return a pointer
43 to it. The pointer shall be suitable for use in a subsequent call to
44 free(). Otherwise, it shall return a null pointer and set errno to
45 indicate the error.
46
48 The tempnam() function shall fail if:
49 ENOMEM Insufficient storage space is available.
51 The following sections are informative.
53
55 Generating a Pathname
56 The following example generates a pathname for a temporary file in
57 directory /tmp, with the prefix file. After the pathname has been cre‐
58 ated, the call to free() deallocates the space used to store the path‐
59 name.
60 #include <stdio.h>
63 #include <stdlib.h>
64 ...
65 const char *directory = "/tmp";
66 const char *fileprefix = "file";
67 char *file;
68 file = tempnam(directory, fileprefix);
70 free(file);
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73 This function only creates pathnames. It is the application's responsi‐
74 bility to create and remove the files. Between the time a pathname is
75 created and the file is opened, it is possible for some other process
76 to create a file with the same name. Applications may find tmpfile()
77 more useful.
78 Applications should use the tmpfile(), mkdtemp(), or mkstemp() func‐
80 tions instead of the obsolescent tempnam() function.
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83 None.
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86 The tempnam() function may be removed in a future version.
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89 fopen(), free(), mkdtemp(), open(), tmpfile(), tmpnam(), unlink()
90 The Base Definitions volume of POSIX.1‐2017, <stdio.h>
92
94 Portions of this text are reprinted and reproduced in electronic form
95 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
96 table Operating System Interface (POSIX), The Open Group Base Specifi‐
97 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
98 Electrical and Electronics Engineers, Inc and The Open Group. In the
99 event of any discrepancy between this version and the original IEEE and
100 The Open Group Standard, the original IEEE and The Open Group Standard
101 is the referee document. The original Standard can be obtained online
102 at http://www.opengroup.org/unix/online.html .
103 Any typographical or formatting errors that appear in this page are
105 most likely to have been introduced during the conversion of the source
106 files to man page format. To report such errors, see https://www.ker‐
107 nel.org/doc/man-pages/reporting_bugs.html .
108IEEE/The Open Group 2017 TEMPNAM(3P)