This example returns information about an attached file system.

 #define INCL_DOSFILEMGR   /* File manager values */
 #define INCL_DOSERRORS    /* DOS error values    */
 #include <os2.h>
 #include <stdio.h>
 #include <string.h>

int main(VOID)
  {
  UCHAR  szDeviceName[8] = "C:";  /* Device name or drive letter string */
  ULONG  ulOrdinal       = 0;     /* Ordinal of entry in name list      */
  PBYTE  pszFSDName      = NULL;  /* pointer to FS name                 */
  PBYTE  prgFSAData      = NULL;  /* pointer to FS data                 */
  APIRET rc              = NO_ERROR; /* Return code                     */

    /* Return-data buffer should be large enough to hold FSQBUFFER2 */
    /* and the maximum data for szName, szFSDName, and rgFSAData    */
    /* Typically, the data isn't that large.                        */

  BYTE         fsqBuffer[sizeof(FSQBUFFER2) + (3 * CCHMAXPATH)] = {0};
  ULONG        cbBuffer   = sizeof(fsqBuffer);        /* Buffer length) */
  PFSQBUFFER2  pfsqBuffer = (PFSQBUFFER2) fsqBuffer;

    rc = DosQueryFSAttach(
                szDeviceName,    /* Logical drive of attached FS      */
                ulOrdinal,       /* ignored for FSAIL_QUERYNAME       */
                FSAIL_QUERYNAME, /* Return data for a Drive or Device */
                pfsqBuffer,      /* returned data                     */
                &cbBuffer);      /* returned data length              */

    /* On successful return, the fsqBuffer structure contains     */
    /* a set of information describing the specified attached     */
    /* file system and the DataBufferLen variable contains        */
    /* the size of information within the structure               */

    if (rc != NO_ERROR) {
       printf("DosQueryFSAttach error: return code = %u\n", rc);
       return 1;
    } else {

       /* The data for the last three fields in the FSQBUFFER2    */
       /* structure are stored at the offset of fsqBuffer.szName. */
       /* Each data field following fsqBuffer.szName begins       */
       /* immediately after the previous item.                    */

       pszFSDName = pfsqBuffer->szName + pfsqBuffer->cbName + 1;
       prgFSAData = pszFSDName + pfsqBuffer->cbFSDName + 1;

       printf("iType     = %d\n", pfsqBuffer->iType);
       printf("szName    = %s\n", pfsqBuffer->szName);
       printf("szFSDName = %s\n", pszFSDName);
       printf("rgFSAData = %s\n", prgFSAData);
    }
   return NO_ERROR;
}