Re: ifstream::read Question
In article <g1josh$bkt$1@solaris.cc.vt.edu>, byte8bits@gmail.com says...
How would I determine the number of bytes that is.read actually read?
// allocate memory
char * buffer;
while (!is.eof())
{
buffer = new char [chunk];
//read data as a block
is.read(buffer, chunk);
//write the read data to stdout
std::cout << buffer;
delete [] buffer;
}
While your original question has been answered, I feel obliged to point
out that the rest of this code falls somewhat short of what you might
want.
First of all, almost loop like your:
while (!is.eof())
will require extra work to get correct results. The stream's eof() will
only return true if you'd reached the end of the file before the last
time you called read.
Second, you're wasting a lot of time and effort on allocating and
deleting your buffer. Right now, you're allocating and deleting the
buffer with each iteration of the loop -- without seeming to accomplish
anything useful by doing so.
Finally, read() does NOT append a nul character to the buffer following
the data it reads, so your use of operator<< (which expects a char* to
represent a nul-terminated string) can cause a problem as well. Instead
of using operator<<, you should really use the ostream's write().
do {
char buffer[chunk];
is.read(buffer, chunk);
std::cout.write(buffer, is.gcount());
} while (is.gcount() > 0);
--
Later,
Jerry.
The universe is a figment of its own imagination.