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Q51326: DOC: tmpfile() Creates a Temporary File in the Root Dir

Article: Q51326
Product(s): Microsoft C Compiler
Version(s): winnt:1.0,2.0,2.1,4.0,5.0,6.0
Operating System(s): 
Keyword(s): kbdocfix kbdocerr kbAccess200fix kbCRT kbVC100 kbVC200 kbVC210 kbVC400 kbVC410 kbVC500
Last Modified: 03-MAY-2001

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The information in this article applies to:

- The C Run-Time (CRT), used with:
   - Microsoft C for MS-DOS, versions 5.1, 6.0, 6.0a, 6.0ax 
   - Microsoft C/C++ for MS-DOS 
   - Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5 
   - Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 4.0, 5.0, 6.0 
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SUMMARY
=======

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

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Keywords          : kbdocfix kbdocerr kbAccess200fix kbCRT kbVC100 kbVC200 kbVC210 kbVC400 kbVC410 kbVC500 kbVC600 
Technology        : kbVCsearch kbAudDeveloper kbCRT
Version           : winnt:1.0,2.0,2.1,4.0,5.0,6.0

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