eglQueryString — return a string describing properties of the EGL client or of an EGL display connection
                char const * eglQueryString(
               | 
              EGLDisplay display, | 
EGLint name); | 
            
display
                
              
            Specifies the EGL display connection.
name
                
              
            
                        Specifies a symbolic constant, one of
                        EGL_CLIENT_APIS,
                        EGL_VENDOR,
                        EGL_VERSION, or
                        EGL_EXTENSIONS.
                    
            eglQueryString returns a pointer to a
            static, zero-terminated string describing properties of the EGL
            client or of an EGL display connection.
            name may be one of the following:
        
EGL_CLIENT_APIS
              
            
                    Returns a string describing which client rendering
                    APIs are supported. The string contains a
                    space-separated list of API names. The list must
                    include at least one of OpenGL,
                    OpenGL_ES, or OpenVG.
                    These strings correspond respectively to values
                    EGL_OPENGL_API,
                    EGL_OPENGL_ES_API, and
                    EGL_OPENVG_API of the
                    eglBindAPI,
                    api argument.
                
EGL_VENDOR
              
            Returns the name of the vendor responsible for this EGL implementation. The format and contents of the string are implementation-dependent.
EGL_VERSION
              
            
                        Returns a version or release number. The
                        EGL_VERSION string is laid out
                        as follows:
                    
                        major_version.minor_version
                        space
                        vendor_specific_info
                    
                        Both the major and minor portions of the version
                        number are numeric. Their values must match the
                        major and
                        minor values returned by
                        eglInitialize.
                    
The vendor-specific information is optional; if present, its format and contents are implementation-specific.
EGL_EXTENSIONS
              
            Returns a space separated list of supported extensions to EGL. If there are no extensions, then the empty string is returned.
                        If display is
                        EGL_NO_DISPLAY, then the
                        EGL_EXTENSIONS string describes
                        the set of supported client
                        extensions. If
                        display is a valid,
                        initialized display, then the
                        EGL_EXTENSIONS string describes
                        the set of display extensions
                        supported by that display. The set of supported
                        client extensions is disjoint from the set of
                        extensions supported by any given display.
                    
            EGL_CLIENT_APIS is supported only if
            the EGL version is 1.2 or greater.
        
            A display of
            EGL_NO_DISPLAY is supported only if the EGL
            version is 1.5 or greater.
        
            NULL is returned on failure.
        
            EGL_BAD_DISPLAY is generated if
            display is not an EGL display connection,
            unless display is
            EGL_NO_DISPLAY and
            name is
            EGL_EXTENSIONS.
        
            EGL_NOT_INITIALIZED is generated if
            display is a valid but uninitialized
            EGLDisplay.
        
            EGL_BAD_PARAMETER is generated if
            name is not an accepted value.
        
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