Winboard Forum

bsmalb wrote:... I'm familiar with Tim Mann's guide and the other basic resources on the web..

So, my questions are:
1. What is the preferred way to turn off stdin and stdout buffering in C++?

... In C++, you can try cout.setf(ios::unitbuf), which is documented in current editions of "The C++ Programming Language," but not older ones. Another C++ method that might work is cout.rdbuf()->setbuf(NULL, 0). Alternatively, you can carefully call cout.flush() after every line you output; again, I don't recommend this.

...familiar with Tim Mann's guide...

...A second way to fix the problem might be to ask your I/O library not to buffer on input. It should then be safe to poll the underlying file descriptor as described above. With C, you can try calling setbuf(stdin, NULL). However, I have never tried this. Also, there could be problems if you use scanf(), at least with certain patterns, because scanf() sometimes needs to read one extra character and "push it back" into the buffer; hence, there is a one-character pushback buffer even if you asked for stdio to be unbuffered. With C++, you can try cin.rdbuf()->setbuf(NULL, 0), but again, I have never tried this.

A third way to fix the problem is to check whether there are characters in the buffer whenever you poll. C I/O libraries generally do not provide any portable way to do this. Under C++, you can use cin.rdbuf()->in_avail(). This method has been reported to work with EXchess. Remember that if there are no characters in the buffer, you still have to poll the underlying file descriptor too, using the method described above.

...May I use a pseudonym?

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Code: Select all


// Here's the OO answer with chewy, carmelly goodness in the center:

   cout.rdbuf()->pubsetbuf(NULL,0);
   cin.rdbuf()->pubsetbuf(NULL,0);