wr_prot.c

Many C samples. It is a good sample for students to learn C language.

#include <dos.h>
char buffer[2048];

int main()
{
  union REGS inregs, outregs;
  struct SREGS segregs;
  char far *bufferp;

  inregs.h.al = 0;   /* drive number 0,1 = a,b: 128,129=c,d */
  inregs.x.cx = 1;   /* sectors to read */
  inregs.x.dx = 0;   /* starting sector number */
  bufferp = buffer;
  inregs.x.bx = FP_OFF(bufferp);
  segregs.ds  = FP_SEG(bufferp);

  int86x(0x25, &inregs, &outregs, &segregs);
  if (outregs.x.cflag == 1)
  {
    printf("error reading drive A\n");
    return 2;
  }

  int86x(0x26, &inregs, &outregs, &segregs);
  if (outregs.x.cflag == 1)
  {
    printf("error writing drive A\n");
    return 1;
  }

   return 0;
}