Re: VS2005 C++ Express basic_istream::get(buf, size, delim) bug
Terry G wrote
Is this a compiler bug? Does your C++ compiler produce the same
results?
Below, cin.get() sets failbit on a blank line, per the standard (see below).
#include <iostream>
#include <limits>
int main() {
static char Line[1024];
while (std::cin.get(Line, sizeof(Line), '\n')) {
std::cin.ignore(std::numeric_limits<int>::max(), '\n');
std::cout << ':' << Line << std::endl;
}
} // main
Mr Tandetnik wrote:
g++ is wrong. C++ standard about basic_istream::get : "27.6.1.3/8 If the
function stores no characters, it calls setstate(failbit)." Once failbit
is set, the stream object would evaluate to false in boolean context.
That's why the loop should terminate on an empty line.
Thank you, Mr Tandetnik.
g++ behaves the same way.
The only reason it appeared to work was that there were carriage returns
before the newline chars.
When I stripped the \r's, g++ set failbit too.
I'm not sure why basic_istream::get() works this way.
I would have prefered reading nothing, setting Line[0] to '\0', and
cin.gcount() == 0, without setting ios::failbit.
I'll bet people smarter than I debated it for months.
Here's updated code that works.
#include <iostream>
#include <limits>
using namespace std;
int main() {
static char Line[1024];
for (;;) {
if (!cin.get(Line, sizeof(Line))) {
if (cin.bad() || cin.eof())
break;
cin.clear();
}
cin.ignore(numeric_limits<int>::max(), '\n');
cout << ':' << Line << endl;
}
} // main