Question

Suppose that this file is 2 and 1/2 blocks long, with block size of 1024.

aBlock = 1024;
char* buffer = new char[aBlock];
while (!myFile.eof()) {
    myFile.read(buffer,aBlock);
    //do more stuff
}

The third time it reads, it is going to write half of the buffer, leaving the other half with invalid data. Is there a way to know how many bytes did it actually write to the buffer?

Answer 1

istream::gcount returns the number of bytes read by the previous read.