readpartial

Reads at most maxlen bytes from the ARGF stream. It blocks only if ARGF has no data immediately available. If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning. It raises EOFError on end of file.

readpartial is designed for streams such as pipes, sockets, and ttys. It blocks only when no data is immediately available. This means that it blocks only when following all conditions hold:

• The byte buffer in the IO object is empty.

• The content of the stream is empty.

• The stream has not reached EOF.

When readpartial blocks, it waits for data or EOF. If some data is read, readpartial returns with the data. If EOF is reached, readpartial raises an EOFError.

When readpartial doesn't block, it returns or raises immediately. If the byte buffer is not empty, it returns the data in the buffer. Otherwise, if the stream has some content, it returns the data in the stream. If the stream reaches EOF an EOFError is raised.