trusty (3) tempnam.3posix.gz

NAME

       tempnam - create a name for a temporary file

SYNOPSIS

       #include <stdio.h>

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

DESCRIPTION

       The tempnam() function shall generate a pathname that may be used for a temporary file.

       The  tempnam()  function allows the user to control the choice of a directory. The dir argument points to
       the name of the directory in which the file is to be created. If dir is a null pointer  or  points  to  a
       string  which  is  not  a  name  for an appropriate directory, the path prefix defined as P_tmpdir in the
       <stdio.h> header shall be used. If that directory is not accessible, an implementation-defined  directory
       may be used.

       Many  applications  prefer their temporary files to have certain initial letter sequences in their names.
       The pfx argument should be used for this. This argument may be a null pointer or point to a string of  up
       to five bytes to be used as the beginning of the filename.

       Some  implementations  of tempnam() may use tmpnam() internally.  On such implementations, if called more
       than {TMP_MAX} times in a single process, the behavior is implementation-defined.

RETURN VALUE

       Upon successful completion, tempnam() shall allocate space for a string, put the  generated  pathname  in
       that  space,  and  return  a pointer to it. The pointer shall be suitable for use in a subsequent call to
       free(). Otherwise, it shall return a null pointer and set errno to indicate the error.

ERRORS

       The tempnam() function shall fail if:

       ENOMEM Insufficient storage space is available.

       The following sections are informative.

EXAMPLES

   Generating a Pathname
       The following example generates a pathname for a temporary file in directory /tmp, with the prefix  file.
       After the filename has been created, the call to free() deallocates the space used to store the filename.

              #include <stdio.h>
              #include <stdlib.h>
              ...
              char *directory = "/tmp";
              char *fileprefix = "file";
              char *file;

              file = tempnam(directory, fileprefix);
              free(file);

APPLICATION USAGE

       This  function  only  creates  pathnames. It is the application's responsibility to create and remove the
       files. Between the time a pathname is created and the file is opened,  it  is  possible  for  some  other
       process to create a file with the same name. Applications may find tmpfile() more useful.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       fopen()  ,  free()  ,  open()  ,  tmpfile()  ,  tmpnam()  ,  unlink()  ,  the  Base Definitions volume of
       IEEE Std 1003.1-2001, <stdio.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers,
       Inc  and  The  Open Group. In the event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard  is  the  referee  document.  The
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .