Xlib: I can not connect to the X server
Hi!
I'm in search of a better GUI programming path :) Now trying Xlib.
Here is a simple program from the Internet
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <X11/Xlib.h>
extern int errno;
int main( void ) {
Display *d;
Window w;
XEvent e;
char *msg = "Hello, World!";
int s;
if( ( d = XOpenDisplay( getenv("DISPLAY" ) ) ) == NULL )
{ // Connect X server
printf( "Can't connect X server: %s\n", strerror( errno ) );
exit( 1 );
}
s = DefaultScreen( d );
w = XCreateSimpleWindow( d, RootWindow( d, s ), 10, 10, 200, 200, 1, BlackPixel( d, s ), WhitePixel( d, s ) );
XSelectInput( d, w, ExposureMask | KeyPressMask );
XMapWindow( d, w );
while( 1 )
{
XNextEvent( d, &e );
if( e.type == Expose )
{
XFillRectangle( d, w, DefaultGC( d, s ), 20, 20, 10, 10 );
XDrawString( d, w, DefaultGC( d, s ), 50, 50, msg, strlen( msg ) );
}
if( e.type == KeyPress ) break;
}
XCloseDisplay( d );
return 0;
}
If you build and run on PC Ubuntu - it works fine
On the STM32MP157C-DK2 board - not working :(
Message in terminal:
Can't connect X server: Success
What am I doing wrong?
Best regards
Alexander
