tmpnam(3S)          (C Programming Language Utilities)           tmpnam(3S)


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

   SYNOPSIS
         #include <stdio.h>

         char *tmpnam (char *s);

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

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

         tmpnam always generates a file name using the path-prefix defined as
         Ptmpdir 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 Ltmpnam bytes, where Ltmpnam 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 directory.  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
         Ptmpdir 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 variable 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 certain
         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 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-e.g., malloc
         failed-or none of the above mentioned attempts to find an appropriate
         directory was successful, a NULL pointer will be returned.

         tempnam fails if there is not enough space.

   FILES
         ptmpdir
                /var/tmp



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   tmpnam(3S)          (C Programming Language Utilities)           tmpnam(3S)


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

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

         Files created using these functions and either fopen or creat 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 remove the file when its use is ended.

         If called more than TMPMAX (defined in stdio.h) times in a single
         process, these functions 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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