text: #include <cwlib.h>include(signatures).
  As well as being used by the library functions that sound Morse code characters and provide a keyer sidetone, the primitive tone queue functions are publicly available to caller programs.
  cwlib calls the external keying function only when the keying state changes. A call is likely each time a tone is taken off the tone queue.
  Characters and strings are converted into representations, and then the correct tones for the dots and dashes in these representations are queued on the tone queue, for action by the background queue emptying process.
  Errors in receiving may be detected by means of the flags passed back on receive character functions.
  cwlib uses system itimers for its internal timing. On most UNIX flavours,; at 60 WPM, the dot length is 20mS, or just two kernel clock ticks. So at higher speeds, the effect of itimer resolutions becomes more pronounced.