write before BOF

[Gorc]

Is there any runtime diagnostic required by C++ standard in


std:fstream ofs("foo.bar");
ofs.seekp(-1,ios::beg);
ofs << "Gosh";

or is the result implementation defined as with writng past eof?

gorc

 

[Frank Birbacher]

Hi!

std:fstream ofs("foo.bar");
ofs.seekp(-1,ios::beg);

I expect this to set the failbit.

Frank