Creating a Protocol of the User Interaction

SWI-Prolog offers the possibility to log the interaction with the user on a file. All Prolog interaction, including warnings and tracer output, are written on the protocol file.

protocol( +File)

  Start protocolling on file File. If there is already a protocol file open then close it first. If File exists it is truncated.

protocola( +File)

  Equivalent to protocol/1, but does not truncate the File if it exists.

noprotocol

  Stop making a protocol of the user interaction. Pending output is flushed on the file.

protocolling( -File)

  Succeeds if a protocol was started with protocol/1 or protocola/1 and unifies File with the current protocol output file.