On Mon, Oct 28, 2013 at 2:53 PM, John Peterson <[email protected]> wrote:
> > > One possible problem I can see with the getpot code: is it legal C++ to > call unget() immediately after a call to seekg or is it possibly invoking > undefined behavior? > > The purpose of unget() seems to be to decrease position of istream by one character (http://www.cplusplus.com/reference/istream/istream/unget/), so I don't see why this would be illegal, unless you are already at the beginning of the stream (?). > Second: I'm not sure I even understand the logic of what's going on > here. You save "Pos", then if the current character is _not_ a comment > character, seekg(Pos) and immediately call istr.unget(). I don't see the > point of tellg()/seekg() here because you could not have moved the cursor > in the interim. I commented out these lines and it fixed my test code and > adjoints_ex3. I'm running the rest of the libmesh examples now and will > commit if they all pass. > > Are you sure it is reading the parameters from the input file and not just assigning the default values? Pos is the position of the first character of the parameter. So, if it intends to go the beginning of the parameter, then it has to decrease its position by one character. For example, if the input parameter is "val", then the output of { istr.seekg(Pos); std::cout << "istr" <<std::endl; } would be "al", and the output of { istr.seekg(Pos); istr.unget(); std::cout << "istr" <<std::endl; } would be "val". > Would you and Subramanya mind testing apple clang again after I patch > getpot and let me know if it works for you? > I will be glad to test. -Manav ------------------------------------------------------------------------------ Android is increasing in popularity, but the open development platform that developers love is also attractive to malware creators. Download this white paper to learn more about secure code signing practices that can help keep Android apps secure. http://pubads.g.doubleclick.net/gampad/clk?id=65839951&iu=/4140/ostg.clktrk _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
