tmpnam(3S)             UNIX System V(C Development Set)              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

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



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tmpnam(3S)             UNIX System V(C Development Set)              tmpnam(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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