DOCERR: tmpfile() Creates a Temporary File in the Root Dir

Last reviewed: September 2, 1997
Article ID: Q51326

The information in this article applies to:
  • The C Run-time (CRT) included with: - Microsoft C for MS-DOS, versions 5.1, 6.0, 6.0a, 6.0ax - Microsoft C/C++ for MS-DOS, version 7.0 - Microsoft Visual C++ for Windows, versions 1.0, 1.5 - Microsoft Visual C++ 32-bit Edition, versions 1.0, 2.0, 2.1, 4.0, 4.1,

         5.0
    

The Microsoft C run-time library function tmpfile() creates a temporary file in the root directory of the current drive. This file has read/write access and is automatically deleted when the file is closed.

The documentation for this function implies that the file will be created in the current working directory. This is not the case; the file will exist only in the root directory. To create a temporary file in a different directory, use the functions tmpnam() or tempnam() in conjunction with fopen().

Some obscure side effects can occur on some systems as a result of tmpfile() creating a file in the root directory. On a network, you must have read/write privileges for the root directory of your current drive. Without these rights, tmpfile() will fail to open the temporary file, returning a NULL in the process.

Another possible reason tmpfile() might fail is if the root directory is full. MS-DOS allows only a limited amount of file entries in the root directory depending on the disk format; therefore, if the root is full, you must delete some files before you use tmpfile().


Additional query words: Novell
Keywords : CRTIss kbfasttip
Version : MS-DOS:5.1,6.0,6.00a,6.00ax,7.0; WINDOWS:1.0,1.5; WINDOWS NT:1.0,2.0,2.1,4.0,4.1,5.0
Platform : MS-DOS NT WINDOWS
Issue type : kbdocerr


THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Last reviewed: September 2, 1997
© 1998 Microsoft Corporation. All rights reserved. Terms of Use.