This example shows how to label the disk in drive "A" as "MYDISK". Before running this program, make sure that there is a disk in the drive.

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

int main(VOID) {

ULONG   DriveNumber   = 1;                    /* Drive 1=A: 2=B: 3=C: ... */
VOLUMELABEL FSInfoBuf = {0};                  /* File system info buffer */
APIRET  rc            = NO_ERROR;             /* Return code */

strcpy(FSInfoBuf.szVolLabel, "MYDISK");    /* Change vol label to MYDISK */
FSInfoBuf.cch = (BYTE) strlen(FSInfoBuf.szVolLabel);

rc = DosSetFSInfo(DriveNumber,            /* Drive number */
                  FSIL_VOLSER,            /* Level of information being set */
                  &FSInfoBuf,             /* Address of input buffer */
                  sizeof(VOLUMELABEL) );  /* Buffer size */
if (rc != NO_ERROR) {
   printf("DosSetFSInfo error: return code = %u\n", rc);
   return 1;
}

return NO_ERROR;
}