This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       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.

       Applications  should  use  the  tmpfile(),  mkdtemp(),  or mkstemp() functions instead of the obsolescent
       tempnam() function.

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group  Base
       Specifications  Issue  7, 2018 Edition, Copyright (C) 2018 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 .

       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.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                                       TEMPNAM(3POSIX)

       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.

       The tempnam() function shall fail if:

       ENOMEM Insufficient storage space is available.

       Thefollowingsectionsareinformative.

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

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

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

       The tempnam() function may be removed in a future version.

       tempnam — create a name for a temporary file

       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.

       None.

       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.

fopen(), free(), mkdtemp(), open(), tmpfile(), tmpnam(), unlink()

       The Base Definitions volume of POSIX.1‐2017, <stdio.h>

       #include <stdio.h>

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