huschi.net

TEMPNAM(3P)                POSIX Programmer's Manual               TEMPNAM(3P)
PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
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 pathname has been cre-
       ated, the call to free() deallocates the space used to store the  path-
       name.
           #include <stdio.h>
           #include <stdlib.h>
           ...
           const char *directory = "/tmp";
           const char *fileprefix = "file";
           char *file;
           file = tempnam(directory, fileprefix);
           free(file);
APPLICATION USAGE
       This function only creates pathnames. It is the application's responsi-
       bility 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.
       Applications  should  use  the tmpfile(), mkdtemp(), or mkstemp() func-
       tions instead of the obsolescent tempnam() function.
RATIONALE
       None.
FUTURE DIRECTIONS
       The tempnam() function may be removed in a future version.
SEE ALSO
       fopen(), free(), mkdtemp(), open(), tmpfile(), tmpnam(), unlink()
       The Base Definitions volume of POSIX.1-2008, <stdio.h>
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri-
       cal and Electronics Engineers,  Inc  and  The  Open  Group.   (This  is
       POSIX.1-2008  with  the  2013  Technical Corrigendum 1 applied.) 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.unix.org/online.html .
       Any  typographical  or  formatting  errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files  to  man page format. To report such errors, see https://www.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                          TEMPNAM(3P)