Name

eglQueryString — return a string describing properties of the EGL client or of an EGL display connection

C Specification

char const * eglQueryString( EGLDisplay display,
  EGLint name);
 

Parameters

display

Specifies the EGL display connection.

name

Specifies a symbolic constant, one of EGL_CLIENT_APIS, EGL_VENDOR, EGL_VERSION, or EGL_EXTENSIONS.

Description

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.

Notes

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.

Errors

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.