Scieneer Common Lisp 1.3.9 online documentation

ext:stream-read-chars stream string start requested waitp[Generic Function]

Attempt to read the requested number of characters from the stream into the given string starting at start, and return the number of characters read or -1 if at the eof-of-file. On pipes or similar devices, this function returns as soon as any data is available, even if the amount read is less than requested and the end-of-file has not been reached. When waitp is true, wait for at least one character before returning, otherwise return zero if no input is available. The stream input buffer is bypassed. Called by read-chars when the stream input buffer is empty. See the documentation for read-chars. Every buffered character input stream must define a method for this function. When less characters are read 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.