Add more GLFW_NO_API documentation

docs/compat.dox

@@ -109,8 +109,8 @@ glfwCreateWindow to fail.
 GLFW uses the `GLX_ARB_create_context_profile` extension to provide support for
 context profiles.  Where this extension is unavailable, setting the
 `GLFW_OPENGL_PROFILE` hint to anything but `GLFW_OPENGL_ANY_PROFILE`, or setting
-`GLFW_CLIENT_API` to anything but `GLFW_OPENGL_API` will cause @ref
-glfwCreateWindow to fail.
+`GLFW_CLIENT_API` to anything but `GLFW_OPENGL_API` or `GLFW_NO_API` will cause
+@ref glfwCreateWindow to fail.
 
 GLFW uses the `GLX_ARB_context_flush_control` extension to provide control over
 whether a context is flushed when it is released (made non-current).  Where this

docs/context.dox

@@ -80,6 +80,14 @@ when writing a command-line only application.  The menu bar setup can be
 disabled with a [compile-time option](@ref compile_options_osx).
 
 
+@subsection context_less Windows without contexts
+
+You can disable context creation by setting the
+[GLFW_CLIENT_API](@ref window_hints_ctx) hint to `GLFW_NO_API`.  Windows without
+contexts may not be passed to @ref glfwMakeContextCurrent or @ref
+glfwSwapBuffers.
+
+
 @section context_current Current context
 
 Before you can make OpenGL or OpenGL ES calls, you need to have a current

docs/window.dox

@@ -223,8 +223,8 @@ This hint is ignored for windowed mode windows.
 @subsubsection window_hints_ctx Context related hints
 
 `GLFW_CLIENT_API` specifies which client API to create the context for.
-Possible values are `GLFW_OPENGL_API` and `GLFW_OPENGL_ES_API`.  This is a hard
-constraint.
+Possible values are `GLFW_OPENGL_API`, `GLFW_OPENGL_ES_API` and `GLFW_NO_API`.
+This is a hard constraint.
 
 `GLFW_CONTEXT_VERSION_MAJOR` and `GLFW_CONTEXT_VERSION_MINOR` specify the client
 API version that the created context must be compatible with.  The exact
@@ -337,7 +337,7 @@ Window hint                     | Default value               | Supported values
 `GLFW_STEREO`                   | `GLFW_FALSE`                | `GLFW_TRUE` or `GLFW_FALSE`
 `GLFW_SRGB_CAPABLE`             | `GLFW_FALSE`                | `GLFW_TRUE` or `GLFW_FALSE`
 `GLFW_DOUBLEBUFFER`             | `GLFW_TRUE`                 | `GLFW_TRUE` or `GLFW_FALSE`
-`GLFW_CLIENT_API`               | `GLFW_OPENGL_API`           | `GLFW_OPENGL_API` or `GLFW_OPENGL_ES_API`
+`GLFW_CLIENT_API`               | `GLFW_OPENGL_API`           | `GLFW_OPENGL_API`, `GLFW_OPENGL_ES_API` or `GLFW_NO_API`
 `GLFW_CONTEXT_VERSION_MAJOR`    | 1                           | Any valid major version number of the chosen client API
 `GLFW_CONTEXT_VERSION_MINOR`    | 0                           | Any valid minor version number of the chosen client API
 `GLFW_CONTEXT_ROBUSTNESS`       | `GLFW_NO_ROBUSTNESS`        | `GLFW_NO_ROBUSTNESS`, `GLFW_NO_RESET_NOTIFICATION` or `GLFW_LOSE_CONTEXT_ON_RESET`
@@ -810,7 +810,7 @@ topmost or always-on-top.  This is controlled by the
 @subsubsection window_attribs_ctx Context related attributes
 
 `GLFW_CLIENT_API` indicates the client API provided by the window's context;
-either `GLFW_OPENGL_API` or `GLFW_OPENGL_ES_API`.
+either `GLFW_OPENGL_API`, `GLFW_OPENGL_ES_API` or `GLFW_NO_API`.
 
 `GLFW_CONTEXT_VERSION_MAJOR`, `GLFW_CONTEXT_VERSION_MINOR` and
 `GLFW_CONTEXT_REVISION` indicate the client API version of the window's context.

include/GLFW/glfw3.h

@@ -3297,6 +3297,10 @@ GLFWAPI void glfwSetTime(double time);
  *  whether a context performs this flush by setting the
  *  [GLFW_CONTEXT_RELEASE_BEHAVIOR](@ref window_hints_ctx) window hint.
  *
+ *  The specified window must have an OpenGL or OpenGL ES context.  Specifying
+ *  a window without a context will generate a @ref GLFW_NO_WINDOW_CONTEXT
+ *  error.
+ *
  *  @param[in] window The window whose context to make current, or `NULL` to
  *  detach the current context.
  *
@@ -3338,6 +3342,10 @@ GLFWAPI GLFWwindow* glfwGetCurrentContext(void);
  *  the swap interval is greater than zero, the GPU driver waits the specified
  *  number of screen updates before swapping the buffers.
  *
+ *  The specified window must have an OpenGL or OpenGL ES context.  Specifying
+ *  a window without a context will generate a @ref GLFW_NO_WINDOW_CONTEXT
+ *  error.
+ *
  *  @param[in] window The window whose buffers to swap.
  *
  *  @par Thread Safety