eglQueryString - EGL Reference Pages

## 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.

## See Also

eglBindAPI, eglGetDisplay, eglInitialize

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