Create a gzip decompression stream that reads from the given source binary stream. Once the stream is open the header time and optional file name may be obtained via ext:gunzip-input-stream-time and ext:gunzip-input-stream-file-name respectively.

:element-type

Indicates the element type to use. Only the character and '(unsigned-byte 8) types are supported. The default is to create an binary '(unsigned-byte 8) stream.

:external-format

The external character format to use. The default value is :default for which the value of ext:*default-external-format* is used.

:close-stream-p

If true then the target stream is closed when this stream is closed.

:allow-concatenated-p

When true, read multiple gzip files concatenated together as a single stream. Otherwise an EOF is returned at the end of the first file in the source stream.

:pathname

When true, the returned stream will be a subclass of the class file-stream. This should generally be true if the stream is a file-stream.