wrapsink "echo" wrapss "echo"
Echo is a stand-along non-PHISH program that can be wrapped with a PHISH minnow so it can be used in a PHISH program. In PHISH lingo, a "minnow" is a stand-alone application which makes calls to the PHISH library to exchange data with other PHISH minnows.
The echo program simply reads lines from stdin and echoes them to stdout. PHISH minnows that can wrap the echo program include the wrapsink and wrapss, which convert stdin/stdout into the receiving and sending of datums.
The echo program does not call the PHISH library and thus does not use PHISH ports directly. But if it is wrapped with the wrapsink or wrapss minnows then they use one input port 0 to receive datums which are then read by the echo program via stdin. If it is wrapped with the wrapss minnow then it uses one output port 0 to send datums that are written to stdout by the echo program.
The echo program simply reads a line of input from stdin and writes it to stdout. See the doc pages for the wrapsink or wrapss minnows for how they convert datums they receive to lines of text that the echo program can read from stdin, and how they convert lines of text that the echo program writes to stdout to datums they send.
The echo program does not call the PHISH library and thus does not deal directly with PHISH data types.
The C++ version of the echo program allocates a buffer of size MAXLINE = 1024 bytes for reading a line from stdin. This can be changed (by editing minnow/echo.cpp) if longer lines are needed.