DosSetDefaultDisk

DosSetDefaultDisk sets the specified drive as the default drive for the process.

Syntax
 ULONG    disknum;  /*  New default-drive number. */ APIRET   ulrc;     /*  Return Code. */

ulrc = DosSetDefaultDisk(disknum); 

Parameters

 * disknum (ULONG) - input : New default-drive number.
 * The value 1 means drive A, 2 means drive B, 3 means drive C, and so on. The maximum possible value is 26, which corresponds to drive Z. Values outside this range will cause an error. (The number of the drive to set as default drive. (A=1, B=2 etc.) )

Returns
ulrc (APIRET) - returns DosSetDefaultDisk returns one of the following values:
 * 0      NO_ERROR
 * 15     ERROR_INVALID_DRIVE

Include Info

 * 1) define INCL_DOSFILEMGR
 * 2) include 

Sample Code
if(DosSetDefaultDisk(4))  /* Set default drive to D: */ {    printf("Can not change default drive to D:\n"); }
 * 1) define INCL_DOSFILEMGR
 * 2) include 
 * 3) include  /* For printf */

This example creates a backup copy of the file "CONFIG.SYS" with the new name "CONFIG.CPY", in the root directory, even if the new file name already exists. 
 * 1) define INCL_DOSFILEMGR  /* File Manager values */
 * 2) define INCL_DOSERRORS   /* DOS error values    */
 * 3) include 
 * 4) include 
 * 5) include 

int main(VOID) { UCHAR  achSourceString[80]  = "config.sys";  /* String to transform */ UCHAR  achEditString[80]    = "*.cpy";       /* Editing string */ UCHAR  achTargetString[200] = "";            /* Destination string buffer */ APIRET rc                   = NO_ERROR;      /* Return code */

rc = DosSetDefaultDisk(3);   /* Set drive to C: (1=A, 2=B, 3=C, ...)      */ if (rc != NO_ERROR) { printf("DosSetDefaultDisk error: return code = %u\n", rc); return 1; }

rc = DosSetCurrentDir ("\\"); /*  Set directory to root */ if (rc != NO_ERROR) { printf("DosSetCurrentDir error: return code = %u\n", rc); return 1; }

/* Transform "CONFIG.SYS" using "*.CPY" to "CONFIG.CPY" */

rc = DosEditName(1, achSourceString, achEditString, achTargetString, 200);

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

/* Copy contents of CONFIG.SYS to the backup file */

rc = DosCopy(achSourceString,            /* Name of file to be copied    */                achTargetString,             /* Name of the target file      */                DCPY_EXISTING);   /* Copy even if target file already exists */

if (rc != NO_ERROR) { printf("DosCopy error: return code = %u\n", rc); return 1; } else printf ("Backup file %s created.\n", achTargetString); return NO_ERROR; } 