Xopendisplay分段错误

Question

我在C中执行了一个简单的X11程序。但由于 XOpenDisplay（NULL），我得到了分段错误（11）。

#include <X11/Xlib.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(void) 
{
Display *display;
Window window;
XEvent event;
char *msg = "Hello, World!";
int s;

/* /2/ some basic X11 setup */
/* open connection with the server */
display = XOpenDisplay(NULL);
if (display == NULL)
{
    fprintf(stderr, "Cannot open display\n");
    exit(1);
}

s = DefaultScreen(display);

/* create window */
window = XCreateSimpleWindow(display, RootWindow(display, s), 10, 10, 200, 200, 1,
                       BlackPixel(display, s), WhitePixel(display, s));

/* select kind of events we are interested in */
XSelectInput(display, window, ExposureMask | KeyPressMask);

/* map (show) the window */
XMapWindow(display, window);

/* /3/ event loop */
for (;;)
{
    XNextEvent(display, &event);

    /* /4/ draw or redraw the window */
    if (event.type == Expose)
    {
        XFillRectangle(display, window, DefaultGC(display, s), 20, 20, 10, 10);
        XDrawString(display, window, DefaultGC(display, s), 50, 50, msg, strlen(msg));
    }
    /* /5/ exit on key press */
    if (event.type == KeyPress)
        break;
}

/* /6/ close connection to server */
XCloseDisplay(display);

return 0;


}

命令行：

gcc -o out test.c -I/usr/X11R6/include/ -L/usr/X11R6/lib/ -lX11

我在Mac终端中执行失败，但它在Xcode中有效。我不知道原因。