Using _dos_findfirst() Function to Retrieve Disk Volume

MS-DOS                      | WINDOWS

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/C++ for MS-DOS, versions 7.0
      - Microsoft Visual C++ for Windows, version 1.0 and 1.5
  

SUMMARY

In Microsoft C, using the _dos_findfirst() function to find a disk volume with the _A_VOLID attribute gets the disk volume correctly unless the volume name is greater than eight characters.

MORE INFORMATION

Volume labels are a specific type of directory entry specified by setting bit 3 in the attribute field to 1 or 0x08. They are a special type of file that can only be in the root directory. The maximum number of characters a volume label can have is 11 characters (8 characters for the filename followed by a three-character extension).

The C run-time function _dos_findfirst() will return the volume label in an 8.3 file format because MS-DOS stores the volume label in the file format. For example, if a disk has a volume label of "A_LONG_NAME", calling _dos_findfirst() with the _A_VOLID attribute will return the volume label as "A_LONG_N.AME".