Question

I am trying to get my client which works with Linux and Windows to work with Mac. I have a log class so I can see what is going on and catch errors but my logfile isn’t even outputting. The logfile is declared globally so it should at least output the logfile header regardless. I am using the terminal version C++ with Xcode.

Here is my log code:

log.h

#ifndef LOG_H
#define LOG_H

#include <fstream>

using namespace std;

class Log
{
public:

        // Constructor / Destructor
        Log();
        ~Log();

        // Class functions
        void writeNewline();
        void writeError(char * text,...);
        void writeSuccess(char * text,...);


private:

        ofstream logfile;
};

#endif

log.cpp

#include <ctime>
#include <stdarg.h>

#include "log.h"

const int BUFFER_SIZE = 1024;

using namespace std;

Log::Log()
{
    // Create a log file for output
    logfile.open ("lanternlog.txt", ios::out);

    // Grab the current system time
    time_t t = time(0);
    struct tm * now = localtime( & t );

    // TODO: Format the time correctly

    // Insert the time and date at the top
    logfile << "<---> Logfile Initialized on " << now->tm_mon + 1 << "-" << 
            now->tm_mday << "-" << now->tm_year + 1900 << " at " << now->tm_hour <<
            ":" << now->tm_min << ":" << now->tm_sec << endl;
}

// Destructor
Log::~Log()
{
    // Close the logfile
    logfile.close();
}

void Log::writeError(char * text,...)
{
    // Grab the variables and insert them
    va_list ap;
    va_start(ap, text);
    char buff[BUFFER_SIZE];
    vsnprintf(buff, sizeof(buff), text, ap);

    // Output to the log
    logfile << "<-!-> " << buff << endl;
}

void Log::writeSuccess(char * text,...)
{
    // Grab the variables and insert them
    va_list ap;
    va_start(ap, text);
    char buff[BUFFER_SIZE];
    vsnprintf(buff, sizeof(buff), text, ap);

    // Output to the log
    logfile << "<---> " << buff << endl;
}

void Log::writeNewline()
{
    // Create a new line in the logfile
    logfile << endl;
}

When the application shuts down, and I have dropped a breakpoint, the logfile should have already output something. There is also a warning with all of my log commands. For instance:

errorLog.writeSuccess("Fatal Error: Unable to initialize Lantern!");

yields: Conversion from string literal to ‘char *’ is deprecated

Still, the main initialization of the logfile does not use this method and should output the file.

First question was solved! Check below for other error:

Edit: It seems I have gotten a tiny bit further. The logfile is created, but is created in the harddrive/users/ folder. How would I have it simply output to the Xcode project folder like with Visual Studio.

Answer 1

I think you can deal with the

Conversion from string literal to ‘char *’ is deprecated

by changing the methods from ones which take char * parameters:

void writeError(char * text,...);
void writeSuccess(char * text,...);

to ones which take const char * parameters

void writeError(const char * text,...);
void writeSuccess(const char * text,...);

The compiler should be worried about passing string literals as parameters to functions which could try to change them.

Is the logfile being created?
I’d try removing everything (using #if 0 … #endif) from the constructor except for a dumb

logfile << "logfile constructed";

to reduce the number of ways it can break.