all_fullscreen.cc

#include <memory>

#include <X11/Xlib.h>
#include <X11/extensions/Xrandr.h>

class unique_display : public std::unique_ptr<Display, int(*)(Display*)> {
 public:
  unique_display(Display *dpy) : std::unique_ptr<Display, int(*)(Display*)>(
      dpy, XCloseDisplay) {}
};

class unique_screen_resources : public std::unique_ptr<XRRScreenResources, void(*)(XRRScreenResources*)> {
 public:
  unique_screen_resources(XRRScreenResources *res) : std::unique_ptr<XRRScreenResources, void(*)(XRRScreenResources*)>(
      res, XRRFreeScreenResources) {}
};

class unique_output_info : public std::unique_ptr<XRROutputInfo, void(*)(XRROutputInfo*)> {
 public:
  unique_output_info(XRROutputInfo *output_info) : std::unique_ptr<XRROutputInfo, void(*)(XRROutputInfo*)>(
      output_info, XRRFreeOutputInfo) {}
};

class unique_crtc_info : public std::unique_ptr<XRRCrtcInfo, void(*)(XRRCrtcInfo*)> {
 public:
  unique_crtc_info(XRRCrtcInfo *crtc_info) : std::unique_ptr<XRRCrtcInfo, void(*)(XRRCrtcInfo*)>(
      crtc_info, XRRFreeCrtcInfo) {}
};

int main(void) {
  unique_display dpy(XOpenDisplay(NULL));
  if (!dpy) return 1;

  unique_screen_resources res(
      XRRGetScreenResources(dpy.get(), RootWindow(dpy.get(), 0)));
  if (!res) return 1;

  for (int output_number = 0; output_number < res->noutput; ++output_number) {
    unique_output_info output_info(
        XRRGetOutputInfo(dpy.get(), res.get(), res->outputs[output_number]));
    if (!output_info) return 1;

    if (output_info->connection == RR_Connected) {
      RRCrtc crtc = 0;
      if (output_info->crtc != 0) {
        crtc = output_info->crtc;
      } else if (output_info->ncrtc) {
        crtc = output_info->crtcs[0];
      }
      unique_crtc_info crtc_info(XRRGetCrtcInfo(dpy.get(), res.get(), crtc));
      if (!crtc_info) return 1;

      RRMode mode = output_info->modes[0];
      XRRSetCrtcConfig(dpy.get(), res.get(), crtc, CurrentTime,
                       crtc_info->x, crtc_info->y, mode,
                       crtc_info->rotation, crtc_info->outputs,
                       crtc_info->noutput);
    }
  }

  return 0;
}

Makefile

all_fullscreen: all_fullscreen.cc
	${CXX} -std=c++11 -lX11 -lXinerama -lXrandr -o $@ $^