(Gtk,Xlib) Main프로그램에서 외부 윈도우 접근하는방법.

#include <stdio.h>
#include <string.h>
 
#include <X11/Xlib.h>
#include <X11/Xatom.h>
 
const unsigned long maxlen = 1024l;
 
Atom utf8_string, wm_client_leader,
        _net_client_list, _net_wm_name, _net_wm_pid;
 
typedef struct {
        const char *name;
        Atom *atom;
} AtomRefType;
 
AtomRefType AtomRefs[] = {
        { "UTF8_STRING",        &utf8_string },
        { "WM_CLIENT_LEADER",        &wm_client_leader },
        { "_NET_CLIENT_LIST",        &_net_client_list },
        { "_NET_WM_NAME",        &_net_wm_name },
        { "_NET_WM_PID",        &_net_wm_pid },
};
 
const int AtomCount = sizeof(AtomRefs) / sizeof(AtomRefType);
 
void some_ewmh_init( Display *dpy )
{
        int j;
        char *names[AtomCount];
        Atom atoms[AtomCount];
 
        if ( dpy == NULL )
                return;
 
        for ( j = 0; j < AtomCount; ++j )
                names[j] = (char *)(AtomRefs[j].name);
 
        XInternAtoms( dpy, names, AtomCount, False, atoms );
 
        for ( j = 0; j < AtomCount; ++j )
                *(AtomRefs[j].atom) = atoms[j];
 
}
 
 
void printWindow( unsigned int indent, Display *dpy, Window win )
{
        int ret, size;
        Atom type, atom_return;
        unsigned int pid;
        unsigned long nitems, bytes_left;
        unsigned char *data;
 
 
        printf( "%*s Window[%d] = { ", indent, "+", win );
 
 
        // _NET_WM_PID (ICCCM)
        data = 0;
        pid = 0;
        ret = XGetWindowProperty( dpy, win, _net_wm_pid,
                                  0, 1l, False, XA_CARDINAL, &atom_return,
                                  &size, &nitems, &bytes_left, &data );
        printf("pid = ");
        if ( ret == Success && data != NULL )
        {
                printf( "%d", pid = *((unsigned long *)data) );
                XFree(data);
        }
        else
                printf("Unknown");
 
        // check this is a leader window
        printf( ", isLeader = " );
        ret = XGetWindowProperty( dpy, win, wm_client_leader,
                                  0, 1l, False, XA_WINDOW, &atom_return,
                                  &size, &nitems, &bytes_left, &data );
 
        if ( ret == Success && data != NULL )
        {
                if ( *((unsigned long *)data) == win )
                        printf("True");
                else
                        printf("False");
 
                XFree(data);
        }
        else if ( pid )
                printf("May be True");
        else
                printf("May be False");
 
        // WM_CLASS
        printf(", class = { ");
 
        ret = XGetWindowProperty( dpy, win, XA_WM_CLASS,
                                  0, maxlen, False, XA_STRING, &atom_return,
                                  &size, &nitems, &bytes_left, &data );
 
        if ( ret == Success && nitems > 0 )
        {
                int k;
                char *name, *endpos;
                name = data;
                endpos = data + nitems;
 
                printf("%s", name);
 
                name += ( strlen(name) + 1/*NULL*/ );
                while ( name < endpos )
                {
                        printf(", %s", name );
                        name += ( strlen(name) + 1/*NULL*/ );
                }
                XFree(data);
        }
        else
                printf("Unknown");
 
        printf(" }");
 
 
        printf(" }\n");
}
 
 
int main()
{
        Display *dpy;
        Window foo, root, parent, *cwins1, *cwins2;
 
        int ret;
        unsigned int nwin1, nwin2, j, k;
 
        if ( ( dpy = XOpenDisplay(NULL) ) == None )
        {
                fprintf( stderr, "Open Display failed.\n" );
                return 1;
        }
        some_ewmh_init(dpy);
 
        root = DefaultRootWindow(dpy);
        cwins1 = NULL;
        ret = XQueryTree( dpy, root, &foo, &foo, &cwins1, &nwin1 );
 
        if ( ret == False || nwin1 < 1 )
        {
                fprintf( stderr, "XQeuryTree(): request failed.\n" );
                return 3;
        }
 
        for ( j = 0; j < nwin1; ++j )
        {
                printWindow( 0, dpy, cwins1[j] );
                cwins2 = NULL;
                ret = XQueryTree( dpy, cwins1[j], &foo, &foo, &cwins2, &nwin2 );
                if ( ret == False || nwin2 < 1 )
                        continue;
                for ( k = 0; k < nwin2; ++k )
                        printWindow( 3, dpy, cwins2[k] );
 
                XFree(cwins2);
        }
 
        XFree(cwins1);
        XCloseDisplay(dpy);
 
        return 0;
}