Fix error return value for glfwGetVideoMode

The function returned a pointer to a zeroed video mode instead of NULL
on error because errors were not propagated up from the platform.

Fixes #1292

README.md

@@ -176,6 +176,7 @@ information on what to include when reporting a bug.
  - Disabled tests and examples by default when built as a CMake subdirectory
  - Removed `GLFW_USE_OSMESA` CMake option enabling the Null platform (#1958)
  - Removed CMake generated configuration header
+ - Bugfix: `glfwGetVideoMode` returned an invalid mode on error (#1292)
  - [Win32] Added a version info resource to the GLFW DLL
  - [Win32] Made hidden helper window use its own window class
  - [Win32] Bugfix: The foreground lock timeout was overridden, ignoring the user

src/cocoa_monitor.m

@@ -549,13 +549,20 @@ GLFWvidmode* _glfwGetVideoModesCocoa(_GLFWmonitor* monitor, int* count)
     } // autoreleasepool
 }
 
-void _glfwGetVideoModeCocoa(_GLFWmonitor* monitor, GLFWvidmode *mode)
+GLFWbool _glfwGetVideoModeCocoa(_GLFWmonitor* monitor, GLFWvidmode *mode)
 {
     @autoreleasepool {
 
     CGDisplayModeRef native = CGDisplayCopyDisplayMode(monitor->ns.displayID);
+    if (!native)
+    {
+        _glfwInputError(GLFW_PLATFORM_ERROR, "Cocoa: Failed to query display mode");
+        return GLFW_FALSE;
+    }
+
     *mode = vidmodeFromCGDisplayMode(native, monitor->ns.fallbackRefreshRate);
     CGDisplayModeRelease(native);
+    return GLFW_TRUE;
 
     } // autoreleasepool
 }

src/cocoa_platform.h

@@ -281,7 +281,7 @@ void _glfwGetMonitorPosCocoa(_GLFWmonitor* monitor, int* xpos, int* ypos);
 void _glfwGetMonitorContentScaleCocoa(_GLFWmonitor* monitor, float* xscale, float* yscale);
 void _glfwGetMonitorWorkareaCocoa(_GLFWmonitor* monitor, int* xpos, int* ypos, int* width, int* height);
 GLFWvidmode* _glfwGetVideoModesCocoa(_GLFWmonitor* monitor, int* count);
-void _glfwGetVideoModeCocoa(_GLFWmonitor* monitor, GLFWvidmode* mode);
+GLFWbool _glfwGetVideoModeCocoa(_GLFWmonitor* monitor, GLFWvidmode* mode);
 GLFWbool _glfwGetGammaRampCocoa(_GLFWmonitor* monitor, GLFWgammaramp* ramp);
 void _glfwSetGammaRampCocoa(_GLFWmonitor* monitor, const GLFWgammaramp* ramp);
 

src/internal.h

@@ -700,7 +700,7 @@ struct _GLFWplatform
     void (*getMonitorContentScale)(_GLFWmonitor*,float*,float*);
     void (*getMonitorWorkarea)(_GLFWmonitor*,int*,int*,int*,int*);
     GLFWvidmode* (*getVideoModes)(_GLFWmonitor*,int*);
-    void (*getVideoMode)(_GLFWmonitor*,GLFWvidmode*);
+    GLFWbool (*getVideoMode)(_GLFWmonitor*,GLFWvidmode*);
     GLFWbool (*getGammaRamp)(_GLFWmonitor*,GLFWgammaramp*);
     void (*setGammaRamp)(_GLFWmonitor*,const GLFWgammaramp*);
     // window

src/monitor.c

@@ -450,7 +450,9 @@ GLFWAPI const GLFWvidmode* glfwGetVideoMode(GLFWmonitor* handle)
 
     _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
 
-    _glfw.platform.getVideoMode(monitor, &monitor->currentMode);
+    if (!_glfw.platform.getVideoMode(monitor, &monitor->currentMode))
+        return NULL;
+
     return &monitor->currentMode;
 }
 

src/null_monitor.c

@@ -109,9 +109,10 @@ GLFWvidmode* _glfwGetVideoModesNull(_GLFWmonitor* monitor, int* found)
     return mode;
 }
 
-void _glfwGetVideoModeNull(_GLFWmonitor* monitor, GLFWvidmode* mode)
+GLFWbool _glfwGetVideoModeNull(_GLFWmonitor* monitor, GLFWvidmode* mode)
 {
     *mode = getVideoMode();
+    return GLFW_TRUE;
 }
 
 GLFWbool _glfwGetGammaRampNull(_GLFWmonitor* monitor, GLFWgammaramp* ramp)

src/null_platform.h

@@ -204,7 +204,7 @@ void _glfwGetMonitorPosNull(_GLFWmonitor* monitor, int* xpos, int* ypos);
 void _glfwGetMonitorContentScaleNull(_GLFWmonitor* monitor, float* xscale, float* yscale);
 void _glfwGetMonitorWorkareaNull(_GLFWmonitor* monitor, int* xpos, int* ypos, int* width, int* height);
 GLFWvidmode* _glfwGetVideoModesNull(_GLFWmonitor* monitor, int* found);
-void _glfwGetVideoModeNull(_GLFWmonitor* monitor, GLFWvidmode* mode);
+GLFWbool _glfwGetVideoModeNull(_GLFWmonitor* monitor, GLFWvidmode* mode);
 GLFWbool _glfwGetGammaRampNull(_GLFWmonitor* monitor, GLFWgammaramp* ramp);
 void _glfwSetGammaRampNull(_GLFWmonitor* monitor, const GLFWgammaramp* ramp);
 

src/win32_monitor.c

@@ -470,13 +470,17 @@ GLFWvidmode* _glfwGetVideoModesWin32(_GLFWmonitor* monitor, int* count)
     return result;
 }
 
-void _glfwGetVideoModeWin32(_GLFWmonitor* monitor, GLFWvidmode* mode)
+GLFWbool _glfwGetVideoModeWin32(_GLFWmonitor* monitor, GLFWvidmode* mode)
 {
     DEVMODEW dm;
     ZeroMemory(&dm, sizeof(dm));
     dm.dmSize = sizeof(dm);
 
-    EnumDisplaySettingsW(monitor->win32.adapterName, ENUM_CURRENT_SETTINGS, &dm);
+    if (!EnumDisplaySettingsW(monitor->win32.adapterName, ENUM_CURRENT_SETTINGS, &dm))
+    {
+        _glfwInputError(GLFW_PLATFORM_ERROR, "Win32: Failed to query display settings");
+        return GLFW_FALSE;
+    }
 
     mode->width  = dm.dmPelsWidth;
     mode->height = dm.dmPelsHeight;
@@ -485,6 +489,8 @@ void _glfwGetVideoModeWin32(_GLFWmonitor* monitor, GLFWvidmode* mode)
                   &mode->redBits,
                   &mode->greenBits,
                   &mode->blueBits);
+
+    return GLFW_TRUE;
 }
 
 GLFWbool _glfwGetGammaRampWin32(_GLFWmonitor* monitor, GLFWgammaramp* ramp)

src/win32_platform.h

@@ -609,7 +609,7 @@ void _glfwGetMonitorPosWin32(_GLFWmonitor* monitor, int* xpos, int* ypos);
 void _glfwGetMonitorContentScaleWin32(_GLFWmonitor* monitor, float* xscale, float* yscale);
 void _glfwGetMonitorWorkareaWin32(_GLFWmonitor* monitor, int* xpos, int* ypos, int* width, int* height);
 GLFWvidmode* _glfwGetVideoModesWin32(_GLFWmonitor* monitor, int* count);
-void _glfwGetVideoModeWin32(_GLFWmonitor* monitor, GLFWvidmode* mode);
+GLFWbool _glfwGetVideoModeWin32(_GLFWmonitor* monitor, GLFWvidmode* mode);
 GLFWbool _glfwGetGammaRampWin32(_GLFWmonitor* monitor, GLFWgammaramp* ramp);
 void _glfwSetGammaRampWin32(_GLFWmonitor* monitor, const GLFWgammaramp* ramp);
 

src/wl_monitor.c

@@ -232,9 +232,10 @@ GLFWvidmode* _glfwGetVideoModesWayland(_GLFWmonitor* monitor, int* found)
     return monitor->modes;
 }
 
-void _glfwGetVideoModeWayland(_GLFWmonitor* monitor, GLFWvidmode* mode)
+GLFWbool _glfwGetVideoModeWayland(_GLFWmonitor* monitor, GLFWvidmode* mode)
 {
     *mode = monitor->modes[monitor->wl.currentMode];
+    return GLFW_TRUE;
 }
 
 GLFWbool _glfwGetGammaRampWayland(_GLFWmonitor* monitor, GLFWgammaramp* ramp)

src/wl_platform.h

@@ -679,7 +679,7 @@ void _glfwGetMonitorPosWayland(_GLFWmonitor* monitor, int* xpos, int* ypos);
 void _glfwGetMonitorContentScaleWayland(_GLFWmonitor* monitor, float* xscale, float* yscale);
 void _glfwGetMonitorWorkareaWayland(_GLFWmonitor* monitor, int* xpos, int* ypos, int* width, int* height);
 GLFWvidmode* _glfwGetVideoModesWayland(_GLFWmonitor* monitor, int* count);
-void _glfwGetVideoModeWayland(_GLFWmonitor* monitor, GLFWvidmode* mode);
+GLFWbool _glfwGetVideoModeWayland(_GLFWmonitor* monitor, GLFWvidmode* mode);
 GLFWbool _glfwGetGammaRampWayland(_GLFWmonitor* monitor, GLFWgammaramp* ramp);
 void _glfwSetGammaRampWayland(_GLFWmonitor* monitor, const GLFWgammaramp* ramp);
 

src/x11_monitor.c

@@ -491,24 +491,31 @@ GLFWvidmode* _glfwGetVideoModesX11(_GLFWmonitor* monitor, int* count)
     return result;
 }
 
-void _glfwGetVideoModeX11(_GLFWmonitor* monitor, GLFWvidmode* mode)
+GLFWbool _glfwGetVideoModeX11(_GLFWmonitor* monitor, GLFWvidmode* mode)
 {
     if (_glfw.x11.randr.available && !_glfw.x11.randr.monitorBroken)
     {
         XRRScreenResources* sr =
             XRRGetScreenResourcesCurrent(_glfw.x11.display, _glfw.x11.root);
-        XRRCrtcInfo* ci = XRRGetCrtcInfo(_glfw.x11.display, sr, monitor->x11.crtc);
+        const XRRModeInfo* mi = NULL;
 
+        XRRCrtcInfo* ci = XRRGetCrtcInfo(_glfw.x11.display, sr, monitor->x11.crtc);
         if (ci)
         {
-            const XRRModeInfo* mi = getModeInfo(sr, ci->mode);
-            if (mi)  // mi can be NULL if the monitor has been disconnected
+            mi = getModeInfo(sr, ci->mode);
+            if (mi)
                 *mode = vidmodeFromModeInfo(mi, ci);
 
             XRRFreeCrtcInfo(ci);
         }
 
         XRRFreeScreenResources(sr);
+
+        if (!mi)
+        {
+            _glfwInputError(GLFW_PLATFORM_ERROR, "X11: Failed to query video mode");
+            return GLFW_FALSE;
+        }
     }
     else
     {
@@ -519,6 +526,8 @@ void _glfwGetVideoModeX11(_GLFWmonitor* monitor, GLFWvidmode* mode)
         _glfwSplitBPP(DefaultDepth(_glfw.x11.display, _glfw.x11.screen),
                       &mode->redBits, &mode->greenBits, &mode->blueBits);
     }
+
+    return GLFW_TRUE;
 }
 
 GLFWbool _glfwGetGammaRampX11(_GLFWmonitor* monitor, GLFWgammaramp* ramp)

src/x11_platform.h

@@ -968,7 +968,7 @@ void _glfwGetMonitorPosX11(_GLFWmonitor* monitor, int* xpos, int* ypos);
 void _glfwGetMonitorContentScaleX11(_GLFWmonitor* monitor, float* xscale, float* yscale);
 void _glfwGetMonitorWorkareaX11(_GLFWmonitor* monitor, int* xpos, int* ypos, int* width, int* height);
 GLFWvidmode* _glfwGetVideoModesX11(_GLFWmonitor* monitor, int* count);
-void _glfwGetVideoModeX11(_GLFWmonitor* monitor, GLFWvidmode* mode);
+GLFWbool _glfwGetVideoModeX11(_GLFWmonitor* monitor, GLFWvidmode* mode);
 GLFWbool _glfwGetGammaRampX11(_GLFWmonitor* monitor, GLFWgammaramp* ramp);
 void _glfwSetGammaRampX11(_GLFWmonitor* monitor, const GLFWgammaramp* ramp);