TMPNAM(3S)           INTERACTIVE UNIX System           TMPNAM(3S)



          NAME
               tmpnam, tempnam - create a name for a temporary file

          SYNOPSIS
               #include <stdio.h>

               char *tmpnam (s)
               char *s;

               char *tempnam (dir, pfx)
               char *dir, *pfx;

          DESCRIPTION
               These functions generate file names that can safely be used
               for a temporary file.

               The tmpnam function always generates a file name using the
               path-prefix defined as P_tmpdir in the <stdio.h> header
               file.  If s is NULL, tmpnam leaves its result in an internal
               static area and returns a pointer to that area.  The next
               call to tmpnam will destroy the contents of the area.  If s
               is not NULL, it is assumed to be the address of an array of
               at least L_tmpnam bytes, where L_tmpnam is a constant
               defined in <stdio.h>; tmpnam places its result in that array
               and returns s.

               Tempnam allows the user to control the choice of a direc-
               tory.  The argument dir points to the name of the directory
               in which the file is to be created.  If dir is NULL or
               points to a string that is not a name for an appropriate
               directory, the path-prefix defined as P_tmpdir in the
               <stdio.h> header file is used.  If that directory is not
               accessible, /tmp will be used as a last resort.  This entire
               sequence can be up-staged by providing an environment vari-
               able TMPDIR in the user's environment, whose value is the
               name of the desired temporary-file directory.

               Many applications prefer their temporary files to have cer-
               tain favorite initial letter sequences in their names.  Use
               the pfx argument for this.  This argument may be NULL or
               point to a string of up to five characters to be used as the
               first few characters of the temporary-file name.

               Tempnam uses malloc(3C) to get space for the constructed
               file name and returns a pointer to this area.  Thus, any
               pointer value returned from tempnam may serve as an argument
               to free [see malloc(3C)].  If tempnam cannot return the
               expected result for any reason, i.e., malloc(3C) failed, or
               none of the above mentioned attempts to find an appropriate
               directory was successful, a NULL pointer will be returned.

          SEE ALSO
               creat(2), unlink(2), fopen(3S), malloc(3C), mktemp(3C),


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          TMPNAM(3S)           INTERACTIVE UNIX System           TMPNAM(3S)



               tmpfile(3S).

          NOTES
               These functions generate a different file name each time
               they are called.

               Files created using these functions and either fopen(3S) or
               creat(2) are temporary only in the sense that they reside in
               a directory intended for temporary use, and their names are
               unique.  It is the user's responsibility to use unlink(2) to
               remove the file when its use is ended.












































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          TMPNAM(3S)           INTERACTIVE UNIX System           TMPNAM(3S)



          CAVEATS
               If called more than 17,576 times in a single process, these
               functions will start recycling previously used names.

               Between the time a file name is created and the file is
               opened, it is possible for some other process to create a
               file with the same name.  This can never happen if that
               other process is using these functions or mktemp, and the
               file names are chosen to render duplication by other means
               unlikely.













































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