函数名: grapherrormsg 
 功  能: 返回一个错误信息串的指针 
 用  法: #include <graphics.h> 
         char *far grapherrormsg(int errorcode); 
 程序例: 
#include <graphics.h> 
 #include <stdlib.h> 
 #include <stdio.h> 
 #include <conio.h> 
#define NONSENSE -50
int main(void) 
 { 
    /* FORCE AN ERROR TO OCCUR */ 
    int gdriver = NONSENSE, gmode, errorcode; 
   /* initialize graphics mode */ 
    initgraph(&gdriver, &gmode, ""); 
   /* read result of initialization */ 
    errorcode = graphresult(); 
   /* if an error occurred, then output a */ 
    /* descriptive error message.          */ 
    if (errorcode != grOk) 
    { 
       printf("Graphics error: %s\n", grapherrormsg(errorcode)); 
       printf("Press any key to halt:"); 
       getch(); 
       exit(1); /* terminate with an error code */ 
    } 
   /* draw a line */ 
    line(0, 0, getmaxx(), getmaxy()); 
   /* clean up */ 
    getch(); 
    closegraph(); 
    return 0; 
 }