Scieneer Common Lisp 1.3.9 online documentation

ext:write-chars stream string &optional start end waitp[Function]

Attempt to write the string from the start to the end position to the stream, returning the number of characters consumed. If waitp is true then wait until all characters have been consumed before returning. When waitp is false, consume as many characters as possible without blocking, returning the number of characters consumed which may be zero. The characters may be buffered in the stream output buffer. When less characters are consumed than requested, the function ext:stream-waiting-file-descriptor may be called to find the file descriptor and directions blocked and when ready the function may be called again to continue the operation.