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/*
** ISWPROT.C - Detect if floppy drive is write protected
**
** public domain by Bob Stout w/ corrections & additions by Wayne King
*/
#include <dos.h>
#ifdef __TURBOC__
#define FAR far
#else
#define FAR _far
#endif
/*
** isWprot()
**
** Parameters: 1 - Drive number (A: = 0, B: = 1)
**
** Returns: -1 - Error
** 0 - Not write protected
** 1 write protected
**
** Note: If drive door is open, an error is returned but the critical
** error handler is NOT tripped
*/
int isWprot(int drive)
{
union REGS regs;
struct SREGS sregs;
char buf[512], FAR *bufptr = (char FAR *)buf; /* Needed by MSC */
/* First read sector 0 */
segread(&sregs);
regs.x.ax = 0x201;
regs.x.cx = 1;
regs.x.dx = drive & 0x7f;
sregs.es = FP_SEG(bufptr);
regs.x.bx = FP_OFF(bufptr);
int86x(0x13, ®s, ®s, &sregs);
if (regs.x.cflag && regs.h.ah != 6)
{
regs.h.ah = 0x00; /* reset diskette subsystem */
regs.h.dl = drive & 0x7f;
int86x(0x13, ®s, ®s, &sregs);
return -1;
}
/* Try to write it back */
segread(&sregs);
regs.x.ax = 0x301;
regs.x.cx = 1;
regs.x.dx = drive & 0x7f;
sregs.es = FP_SEG(bufptr);
regs.x.bx = FP_OFF(bufptr);
int86x(0x13, ®s, ®s, &sregs);
return (3 == regs.h.ah);
}
#ifdef TEST
#include <stdio.h>
#include <ctype.h>
int main(int argc, char *argv[])
{
int drive;
if (2 > argc)
{
puts("Usage: ISWPROT drive_letter");
return -1;
}
drive = toupper(argv[1][0]) - 'A';
printf("isWprot(%c:) returned %d\n", drive + 'A', isWprot(drive));
return 0;
}
#endif
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