Regarding log file

[mamul]

Hi All,
Could u please help to create a log file for my c++ file read/write operation.
In my project i have written a file main.cpp and file.cpp.
file .cpp implements read/write opeartion for a file. How to create alog file for this which will be display all debuging information during debugging.

suppose there is file named file1.cpp
my question is this log file will take the same file1.cpp file to display the login implementation or it will create another file to store login implementation.

Please reply me as soon as possible with the code itself...
please give me some code on log file.


Advance Thanks to All.

[donbock]

Are you talking about sprinkling calls to some log-write function throughout your code; or are you talking about some built-in log feature available in your run-time environment (such as a debugger)?

If you're using your own log-write function then you can be confident that the log information will only be written to the file you explicitly open. However, you may elect to use one of the built-in files: stdin, stdout, or stderr. You don't have to open or close these standard files; and most shells allow you to redirect to a file.

You should consider whether built-in macros __LINE__, __FILE__, __TIME__, or __DATE__ have a place in your log messages.

After you're done debugging don't go back and delete all your log calls. Instead, find an easily reversible way to convert them into no-ops. The log invocations document something about what your code isn't supposed to do; maintenance programmers may find that insight helpful. Besides, you may want to debug later changes to this program sometime in the future. It would be nice if you could change one line and turn all the logging back on.

Have you considered using assert instead of a roll-your-own log utility?

If you're ambitious, you might consider a printf-style variable argument list for your write-log function. If so, then you should take a look at <stdarg.h> and vfprintf. On the other hand, if you're having trouble with the basic log capability then don't stir in variable arguments until after you've figured out the basic capability. You don't want to have too many balls in the air.

Do you have a multi-tasking or multi-threaded application? If so, then logging can become much trickier because you can get the log message for a higher priority thread appearing in the middle of the log message for a lower priority thread. In this case you may want to put the code that writes to the log file in a separate task and queue log messages to it from the other tasks. This is more of a client-server model.

This is not meant to be a site that merely does your coding for you. Besides, you haven't specified your needs well enough -- we would have to guess what is most important for you in a debugging message. Better for you to work this through yourself -- nobody knows what information is most helpful for debugging than you.

[AmeL]

In the log file, there should be included :
- date of logging
- file : in what file that produces the log ?
- function : in what function ?
- line : the line number
- debug level : in which level is this log ?
- status : success... failed, ... error code ...etc
- desc : the error description.
This is the incomplete sample code to log something:

Full code removed, please read posting guidelines
 

We need to have debug level because each level could state something about the bug clearer and clearer.
the function entry and exit is the good habit of programming, because it will facilitate the task of debugging through the code.

Thanks
/AmeL

[donbock]

What follows illustrates one way to remove all logging from production code while keeping the ability to quickly reinstall the logging facility during development. This is a compile-time mechanism; you may prefer a run-time mechanism that leaves the debug code present.

full code removed, please read posting guidelines

[mamul]

Thanks to All, Now I have got some Idea about log file. Thank u.