DOCERR: tmpnam() Operation Does Not Change If P_tmpdir Modified

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, and 6.0ax
      - Microsoft C for OS/2, versions 6.0, and 6.0a
      - Microsoft C/C++ for MS-DOS, version 7.0
      - Microsoft Visual C++ for Windows, versions 1.0 and 1.5
      - Microsoft Visual C++ 32-bit Edition, versions 1.0, 2.0, 4.0,
        4.1, 5.0
  

In Microsoft C, the documentation for the functions tmpnam(), tempnam() and _tempnam() states that under certain conditions they create a name that consists of the path prefix defined by the P_tmpdir entry in STDIO.H. This is ambiguous. A better way of stating this is that they create a name that consists of a path prefix to the root of the current drive; this is also what P_tmpdir is defined as. However, P_tmpdir is defined as the root directory on the default drive, which is where the created name would reside. However, any modification of P_tmpdir in STDIO.H does not change the filename that is created.

The documentation states that changing the definition of P_tmpdir or L_tmpnam does not change the operation of tmpnam(). Nor does it change the operation of tempnam() or _tempnam(). These two defines are provided only for XENIX/UNIX portability. The three functions tmpnam(), tempnam() and _tempnam() do not make use of these two defines.

Keywords          : CRTIss
Version           : MS-DOS: 5.1, 6.0, 6.00a, 6.00ax, 7.0; OS/2: 6.0, 6.00a; WINDOWS: 1.0, 1.5; WINDOWS NT: 1.0, 2.0, 4.0, 4.1, 5.0
Platform          : NT OS/2 WINDOWS
Issue type        : kbdocerr