standard-library

In the book "The C Programming Language" it says: "Many of the functions in the library set status indicators when error or end of file occur. These indicators may be set and tested explicitly. In addition, the integer expression errno (declared in <errno.h> ) may contain an error number that gives further information about the most recent error." Where can I see a list of these functions? The standard says this about errno : The value of errno is zero at program startup, but is never set to zero by any library function. The value of errno may be set to nonzero by a library function call

In the concurrency library GHC.Conc there is a function called numCapabilities . Its type is numCapabilities :: Int and it actually returns some number you passed by the command line flag (e.g. 5 if the options are +RTS -N 5 ). However, getArgs (type: IO [String] ) does essentially the same (it returns the unparsed non-runtime arguments) but isn't a pure function. If the only excuse is that numCapabilities is often needed in pure code, in what way aren't other command line options not needed in pure code? Am I something missing or is either numCapabilities a design flaw or am I allowed to

The numeric_limits traits is supposed to be a general way of obtaining various type infomation, to be able to do things like template<typename T> T min(const std::vector<T>& vect) { T val = std::numeric_limits<T>::min(); for(int i=0 ; i<vect.size() ; i++) val = max(T, vect[i]); return val; } The problem is that (at least using MS Visual Studio 2008) numeric_limits<int>::min() returns the smallest negative number, while numeric_limits<double>::min() returns the smallest positive number! Anyone knows the rationalie behind this design? Is there a better (recommended?) way of using numeric_limits?

Is it me or are there no standard trim functions in the c or c++ library? is there any single function that acts as a trim? If not can anyone tell me Why trim is not part of the standard library? (i know trim is in boost) My trim code is std::string trim(const std::string &str) { size_t s = str.find_first_not_of(" \n\r\t"); size_t e = str.find_last_not_of (" \n\r\t"); if(( string::npos == s) || ( string::npos == e)) return ""; else return str.substr(s, e-s+1); } test: cout << trim(" \n\r\r\n \r\n text here\nwith return \n\r\r\n \r\n "); -edit- i mostly wanted to know why it wasnt in the

This question already has an answer here: Change priorityQueue to max priorityqueue 14 answers The Priority Queue implementation in the Java standard library appears to be a min Priority Queue which I found somewhat confusing. In order to turn it into a max one I created a custom comparator object. Comparator<Integer> cmp = new Comparator<Integer>() { public int compare( Integer x, Integer y ) { return y - x; } }; I was wondering if there was a more elegant solution. Essentially I wan't a generic priority queue that could be used to implement Dijkstras etc. I didn't even realise there would be

Closed . This question is opinion-based. It is not currently accepting answers. Learn more . Want to improve this question? Update the question so it can be answered with facts and citations by editing this post . Recently, I've got a dangerous idea into my head after reading this blog post. That idea can be expressed like this: I don't need most of what the C++ standard library offers. So, why don't I implement a less general, but easier to use version? As an example, using the STL spits out reams of incomprehensible and mangled compiler errors. But, I don't care about allocators, iterators