Coloured Error Messages for Console Applications

Prateek Kumar Dubey

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5 Dec 2006CPOL

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Implementation of a function which will print coloured messages on console window

Introduction

While working with console applications, sometimes we want to print coloured error messages. Here is the implementation of a very small function which will help in accomplishing the task.

C++

int _teprintf(TCHAR *format, ...) 
{
    HANDLE hStdOut = NULL ;
    TCHAR szBuffer[1024] ;
    va_list arg_list ;
    int nBuf = 0 ;
    va_start(arg_list,format);
    nBuf = _vsntprintf(szBuffer,1024,format,arg_list) ;
    va_end(arg_list) ;
    //get console output handle
    hStdout = GetStdHandle(STD_OUTPUT_HANDLE);    
    if(!hStdout) {
        return 0;
    }
    //set red colour
    if (! SetConsoleTextAttribute(hStdout, FOREGROUND_RED | 
        FOREGROUND_INTENSITY)) {
        return 0;
    }
    //print 
    nBuf = _tprintf(_T("%s"),szBuffer) ;
    //restore to white.
    if (! SetConsoleTextAttribute(hStdout, FOREGROUND_RED |
        FOREGROUND_BLUE | 
        FOREGROUND_GREEN)) {
        return 0;
    }
    return nBuf ;
}

You can use it as follows:

C++

int _tmain(int argc, _TCHAR* argv[])
{
	_teprintf(_T("\nI am Error\n")) ;
	_tprintf(_T("\nI am Normal\n")) ;
	return 0;
}

Though this is trivial, it is fun..!

History

5^th December, 2006: Initial post

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Written By

Prateek Kumar Dubey

Other Microsoft

India

I am currently working with Microsoft at Bangalore (India). My interest lies in areas of generic C++ and windows development. Apart from office hours I try to develop new and useful small tools.
Well, I still feel that I need to be more serious..!
Smile | :)

main.cpp ... console::console_buffer<char> out_buf(console::console_buffer<char>::output); std::basic_streambuf<char>* prev_out_buf = std::wcout.rdbuf(&out_buf); ... console::color green_color(color::foreground<color::green>::value | color::foreground<color::intensity>::value); std::cout << green_color << "TEKISUTO WA MIDORIIRO DESU" << console::def_color << std::endl; .... color.hpp ... class color { public: enum colour { blue = FOREGROUND_BLUE, green = FOREGROUND_GREEN, red = FOREGROUND_RED, intensity = FOREGROUND_INTENSITY }; template<colour c> struct foreground { enum { value = c }; }; template<colour c> struct background { enum { value = c << 4 }; }; explicit color(short c) : c_(c) { } color() : c_(foreground<red>::value | foreground<green>::value | foreground<blue>::value) { } short get() const { return c_; } //! set a new color template<typename charT> friend std::basic_ostream<charT>& operator << (std::basic_ostream<charT>& os, color const& c); private: short c_; }; template<typename charT> inline std::basic_ostream<charT>& operator << (std::basic_ostream<charT>& os, color const& c) { if(os.good()) { //! get current stream buffer if(console_buffer<charT>* screen = dynamic_cast<console_buffer<charT>* >(os.rdbuf())) { os.flush(); static_cast<void>(screen->set_color(c)); } } return os; } ... console_buffer.hpp ... template<typename charT, typename traitsT = std::char_traits<charT> > class console_buffer : public std::basic_filebuf<charT, traitsT> { public: //! available console type enum console_type { devnul = 0, output = STD_OUTPUT_HANDLE, input = STD_INPUT_HANDLE, error = STD_ERROR_HANDLE }; explicit console_buffer(console_type con_type) : con_type_(con_type) , console_(0) { HANDLE h = ::GetStdHandle(con_type); //! ran under service or /dev/nul if(con_type == devnul || h == 0) { h = ::CreateFileW(L"NUL", GENERIC_READ, 0, NULL, OPEN_EXISTING, 0, 0); con_type = devnul; } if(INVALID_HANDLE_VALUE == h) throw std::runtime_error("invalid handle value"); //! if not /dev/nul, should duplicate handle if(con_type != devnul) { HANDLE dup(0); HANDLE process(GetCurrentProcess()); if(!::DuplicateHandle(process, h, process, &dup, 0, 0, DUPLICATE_SAME_ACCESS)) throw std::runtime_error("duplicate error"); h = dup; } //! opend file descriptor int handle = ::_open_osfhandle(reinterpret_cast<::intptr_t>(h), _O_TEXT); //! open C file stream console_ = ::_fdopen(handle, "a"); //! initialize basic_filebuf std::basic_filebuf<charT, traitsT>::_Init(console_, std::basic_filebuf<charT, traitsT>::_Newfl); default_color_ = this->do_get_default_color(); } //! return default screen buffer color color default_color() const { return default_color_; } //! set new screen buffer color color set_color(color const& _new_color) { HANDLE h = this->get_console_handle(); if(INVALID_HANDLE_VALUE != h) { ::CONSOLE_SCREEN_BUFFER_INFO info = { sizeof(CONSOLE_SCREEN_BUFFER_INFO), 0 }; if(::GetConsoleScreenBufferInfo(h, &info)) { color prev(info.wAttributes & 0x00ff); ::SetConsoleTextAttribute(h, (info.wAttributes & 0xff00) | _new_color.get()); return prev; } } return color(); } ... private: color do_get_default_color() const { HANDLE h = this->get_console_handle(); if(INVALID_HANDLE_VALUE != h) { ::CONSOLE_SCREEN_BUFFER_INFO info = { sizeof(CONSOLE_SCREEN_BUFFER_INFO), 0 }; if(::GetConsoleScreenBufferInfo(h, &info)) return color(info.wAttributes & 0x00ff); } return color(); } //! return current console handle HANDLE get_console_handle() const { HANDLE h = INVALID_HANDLE_VALUE; int fd = ::_fileno(console_); if(fd != -1) h = reinterpret_cast<HANDLE>(::_get_osfhandle(fd)); return h; } private: console_type con_type_;//! console type ::FILE* console_; //! C file stream color default_color_;//! defaulr console color }; ... template<typename charT> inline std::basic_ostream<charT>& def_color(std::basic_ostream<charT>& os) { if(os.good()) { //! //! get current stream buffer if(console_buffer<charT>* screen = dynamic_cast<console_buffer<charT>* >(os.rdbuf())) { os.flush(); static_cast<void>(screen->set_color(screen->default_color())); } } return os; }

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Coloured Error Messages for Console Applications

Introduction

History

License

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