#include <graphics.h> void sector(int x, int y, int stangle, int endangle, int xradius, int yradius);
The angles for sector are given in degrees. They are measured counter-clockwise with 0 degrees at 3 o'clock, 90 degrees at 12 o'clock, and so on.
If an error occurs while the pie slice is filling, graphresult returns a value of -6 (grNoScanMem).
/* sector example */ 
#include <graphics.h<
#include <stdlib.h<
#include <stdio.h<
#include <conio.h<
int main(void)
{
   /* request autodetection */
   int gdriver = DETECT, gmode, errorcode;
   int midx, midy, i;
   int stangle = 45, endangle = 135;
   int xrad = 100, yrad = 50;
   /* initialize graphics and local variables */
   initgraph(&gdriver, &gmode, "");
   /* read result of initialization */
   errorcode = graphresult();
   if (errorcode != grOk) {  /* an error occurred */
      printf("Graphics error: %s\n", grapherrormsg(errorcode));
      printf("Press any key to halt:");
      getch();
      exit(1);               /* terminate with an error code */
   }
   midx = getmaxx() / 2;
   midy = getmaxy() / 2;
   /* loop through the fill patterns */
   for (i=EMPTY_FILL; i<USER_FILL; i++) {
      /* set the fill style */
      setfillstyle(i, getmaxcolor());
      /* draw the sector slice */
      sector(midx, midy, stangle, endangle, xrad, yrad);
      getch();
   }
   /* clean up */
   closegraph();
   return 0;
}