On Monday 31 October 2005 12:49, John Love-Jensen wrote: > Hi marcel, > > > can someone explain it to me? > > The *STANDARD* says that pop_back on an empty std::vector has an undefined > effect. > > The safer version you suggest complies with the standard -- but it's not > reliable behavior on all C++ compilers, and it has a performance penalty for > code that does not expect nor rely upon the safe behavior you've suggested. > Even though the performance penalty is slight, it is enough that certain > situations may opt not to use std::vector because of the performance > overhead. > > You can get that same safe behavior by doing a if(v.size()) v.pop_back(); in > your code. Or better yet, create a marcel::vector template class that adds > the additional safety feature you desire *AND* is cross-platform compatible. > That same guarantee cannot be made of the std:: namespace's implementation > of std::vector. > > HTH, > --Eljay > > thanks for clarify. i'll think i'll implement my own templates for the std::<classes> with extended safety. regards marcel
