Re: [boost] logging library?

From: John Torjo (john.lists_at_[hidden])
Date: 2004-04-20 11:13:16

>It's needed copy contructor for temporaries:
>
>  
>
Right on :D Thanks for pointing it out. I used it in a different manner 
before, and there was no need for it.

>Second, gcc doesn't accept "log" for namespace name. 
>
>  
>
Got it. Here's the new version:

#include <iosfwd>
#include <sstream>

namespace boost { namespace logtl /* note: gcc does not allow 'log' as a 
namespace */{

// allow finding the prototype for a log function
template<class char_type, class traits = ::std::char_traits<char_type>, 
class aloc = ::std::allocator<char_type> >
struct log_func {
    typedef void (*type)(const std::basic_string<char_type,traits,aloc> &);
};

// allow writing to a log
template<class char_type, class traits = ::std::char_traits<char_type>, 
class aloc = ::std::allocator<char_type> >
struct basic_logstream {
private:
    typedef typename log_func<char_type,traits,aloc>::type log_func_type;
    typedef ::std::basic_ostringstream<char_type,traits,aloc> 
ostring_stream_type;
    typedef ::std::basic_ostream<char_type,traits> ostream_type;
public:
    explicit basic_logstream( log_func_type func) : m_func(func) {}
    basic_logstream( const basic_logstream & other) : m_func(other.m_func) {
        m_buffer << other.m_buffer.str();
        other.m_func = 0;
    }
    ~basic_logstream() {
        if ( m_func)
            m_func( m_buffer.str() );
    }

    template< class T>
    basic_logstream & operator<<( const T & val) {
        m_buffer << val;
        return *this;
    }
    typedef std::ostream & (*ostream_func)(std::ostream & );
    basic_logstream & operator<<( ostream_func f) {
        f( m_buffer);
        return *this;
    }
    // in case the underlying stream is needed...
    ostream_type & ostream() {
        return m_buffer;
    }
private:
    ostring_stream_type m_buffer;
    mutable log_func_type m_func;
};

typedef basic_logstream<char> logstream;
typedef basic_logstream<wchar_t> wlogstream;

}}

Best,
John