Returns the contents of the clipboard as a string.
This function returns the contents of the system clipboard, if it contains
or is convertible to a UTF-8 encoded string. If the clipboard is empty or
if its contents cannot be converted,
NULL is returned and a @ref
GLFW_FORMAT_UNAVAILABLE error is generated.
$windowDeprecated. Any valid window or
stringThe contents of the clipboard as a UTF-8 encoded string, or