Q41025: Using _dos_setdrive and _searchenv to Open a File

Article: Q41025
Product(s): See article
Version(s): 2.00
Operating System(s): MS-DOS
Keyword(s): ENDUSER | | mspl13_c
Last Modified: 28-FEB-1989

Question:

How can I open a file on a floppy drive without explicitly specifying
a full path in the fopen statement?

Response:

You can use the run-time function _dos_setdrive to set the current
drive to floppy Drive A. Then use the function _searchenv to search
for the filename on a floppy disk in Drive A. The full path to the
specified file will be copied to the buffer. Then you can use fopen to
open the file specified by the buffer.

Note: _searchenv works properly using QuickC Version 2.00. This
program will not work correctly under the earlier versions of QuickC
or C Version 5.10.

The following is a sample code:

#include <dos.h>
#include <stdio.h>
#include <stdlib.h>

main()
{
    FILE *stream;
    unsigned drive;
    char buffer[40];

    /* set default drive to be drive A */
    _dos_setdrive (1, &drive);
    _dos_getdrive (&drive);
    printf( "Current drive: %c:\n", 'A' + drive - 1 );

    /* Search for file at root level */
    _searchenv("data","",buffer);
    printf("path: %s\n", buffer);

    if ((stream = fopen(buffer,"r")) == NULL)
       printf ("Could not open file\n");
    else
       printf("File opened for reading\n");
}

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