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36 .\" @(#)tmpnam.3 8.2 (Berkeley) 11/17/93
46 .Nd temporary file routines
48 .Fd #include <stdio.h>
52 .Fn tmpnam "char *str"
54 .Fn tempnam "const char *tmpdir" "const char *prefix"
59 returns a pointer to a stream associated with a file descriptor returned
62 The created file is unlinked before
64 returns, causing the file to be automatically deleted when the last
65 reference to it is closed.
66 The file is opened with the access value
72 returns a pointer to a file name, in the
75 did not reference an existing file at some indeterminate point in the
78 is defined in the include file
84 the file name is copied to the buffer it references.
85 Otherwise, the file name is copied to a static buffer.
88 returns a pointer to the file name.
90 The buffer referenced by
92 is expected to be at least
96 is defined in the include file
104 but provides the ability to specify the directory which will
105 contain the temporary file and the file name prefix.
107 The environment variable
109 (if set), the argument
117 are tried, in the listed order, as directories in which to store the
124 is used to specify a file name prefix, which will be the
125 first part of the created file name.
127 allocates memory in which to store the file name; the returned pointer
128 may be used as a subsequent argument to
134 returns a pointer to an open file stream on success, and a
144 return a pointer to a file name on success, and a
152 may fail and set the global variable
154 for any of the errors specified for the library functions
164 for any of the errors specified for the library function
172 for any of the errors specified for the library functions
188 These interfaces are provided for System V and
193 interface is strongly preferred.
195 There are four important problems with these interfaces (as well as
199 First, there is an obvious race between file name selection and file
200 creation and deletion.
201 Second, most historic implementations provide only a limited number
202 of possible temporary file names (usually 26) before file names will
203 start being recycled.
204 Third, the System V implementations of these functions (and of
208 function to determine whether or not the temporary file may be created.
209 This has obvious ramifications for setuid or setgid programs, complicating
210 the portable use of these interfaces in such programs.
211 Finally, there is no specification of the permissions with which the
212 temporary files are created.
214 This implementation does not have these flaws, but portable software
215 cannot depend on that.
218 interface should not be used in software expected to be used on other systems
219 if there is any possibility that the user does not wish the temporary file to
220 be publicly readable and writable.