#include <dos.h>

clrwin(row1, col1, row2, col2, attr)
int row1, col1, row2, col2, attr;
{
   union REGS regs;

   regs.x.ax = 0x600;
   regs.h.bh = attr;
   regs.x.cx = (row1 << 8) | col1;
   regs.x.dx = (row2 << 8) | col2;
   int86(0x10, &regs, &regs);
}
