Regular output (the actual result of running the program) should go on `stdout`, things like you mentioned (e.g. diagnostic, notice, warning, error) on `stderr`.

If there is no &quot;regular output&quot;, I would say that it doesn&#39;t really matter which one you choose. You could argue that the logging is the only output, so that should go to `stdout`. Or you could argue that it is still &quot;exceptional information&quot; which should go to `stderr`.

Do you write something else to `stdout`? If the answer is `Yes` then it would be quite hard for someone to distinguish between normal flow and errors in the middle of the file that was used to redirect from `stdout`.

What if `stdout` will be used as input for another program? Will it be able to parse this debug information? In this case it would be good to write only critical errors to `stderr`. If you need to write something else you may consider to write to additional log file.

I have below code in C#

    Dictionary&lt;string, object&gt; dObject = new Dictionary&lt;string, object&gt;();

I want to convert `dObject` to `Dictionary&lt;string, string&gt;`.  How can I do this?

How to convert Dictionary&lt;string, object&gt; to Dictionary&lt;string, string&gt; in c#

I have a `vector&lt;data&gt; info` where `data` is defined as:

    struct data{
        string word;
        int number;
    };

I need to sort `info` by the length of the word strings. Is there a quick and simple way to do it?

sorting a vector of structs

I have a program I&#39;m writing that I want to write a custom logging facility for (e.g. diagnostic, notice, warning, error).

Should I be using the `stdout` or the `stderr` stream to do this? It is an interpreter of sorts and the user can ask it to print output.

**Edit:** Please stop recommending me logging frameworks :(

Should I log messages to stderr or stdout?

I have a program I'm writing that I want to write a custom logging facility for (e.g. diagnostic, notice, warning, error).
Should I be using the <code>stdout</code> or the <code>stderr</code> stream to do this? It is an interpreter of sorts and the user can ask it to print output.
Edit: Please stop recommending me logging frameworks :(

I have my config setup to handle a bunch of GET requests which render pixels that work fine to handle analytics and parse query strings for logging. With an additional third party data stream, I need to handle a POST request to a given url that has JSON in an expected loggable format inside of it&#39;s request body. I don&#39;t want to use a secondary server with `proxy_pass` and just want to log the whole response into an associated log file like what it does with GET requests. A snippet of some code that I&#39;m using looks like the following:

GET request (which works great):

    location ^~ /rl.gif {
      set $rl_lcid $arg_lcid;
      if ($http_cookie ~* &quot;lcid=(.*\S)&quot;)
      {
        set $rl_lcid $cookie_lcid;
      }
      empty_gif;
      log_format my_tracking &#39;{ &quot;guid&quot; : &quot;$rl_lcid&quot;, &quot;data&quot; : &quot;$arg__rlcdnsegs&quot; }&#39;;
      access_log  /mnt/logs/nginx/my.access.log my_tracking;
      rewrite ^(.*)$ http://my/url?id=$cookie_lcid? redirect;
    }

Here is kinda what I am trying to do:
POST request (which does not work):

    location /bk {
      log_format bk_tracking $request_body;
      access_log  /mnt/logs/nginx/bk.access.log bk_tracking;
    }

Curling `curl http://myurl/bk -d name=example` gives me a 404 page not found.

Then I tried:

    location /bk.gif {
      empty_gif;
      log_format bk_tracking $request_body;
      access_log  /mnt/logs/nginx/bk.access.log bk_tracking;
    }

Curling `curl http://myurl/bk.gif -d name=example` gives me a `405 Not Allowed`.

My current version is `nginx/0.7.62`. Any help in the right direction is very much appreciated! Thanks!

***UPDATE***
So now my post looks like this:

    location /bk {
      if ($request_method != POST) {
        return 405;
      }
      proxy_pass $scheme://127.0.0.1:$server_port/dummy;
      log_format my_tracking $request_body;
      access_log  /mnt/logs/nginx/my.access.log my_tracking;
    }
    location /dummy { set $test 0; }

It is logging the post data correctly, but returns a 404 on the requesters end. If I change the above code to return a 200 like so:

    location /bk {
      if ($request_method != POST) {
        return 405;
      }
      proxy_pass $scheme://127.0.0.1:$server_port/dummy;
      log_format my_tracking $request_body;
      access_log  /mnt/logs/nginx/my.access.log my_tracking;
      return 200;
    }
    location /dummy { set $test 0; }

Then it return the `200` correctly, but no longer records the post data.

**ANOTHER UPDATE**
Kinda found a working solution. Hopefully this can help other on their way.

Logging POST data from $request_body

Is there a way to make any function output a console.log statement when it&#39;s called by registering a global hook somewhere (that is, without modifying the actual function itself) or via some other means?

Adding console.log to every function automatically

I would like to implement logging in my application, but would rather not use any outside frameworks like log4net.

So I would like to do something like DOS&#39;s [echo][1] to a file. What is the most effective way to do it?

Is there a way to log unhandled exceptions logged without using an outside framework?

  [1]: https://ss64.com/nt/echo.html


How do I do logging in C# without using 3rd party libraries?

Some people are using [ELMAH][1] instead of log4net. What makes it better?

I found out about ELMAH in [an answer to Stack Overflow question *How do I do logging in C#?*][2]

  [1]: https://elmah.github.io/
  [2]: https://stackoverflow.com/questions/5057567/how-do-i-do-logging-in-c/5057621#5057621


What is the difference between log4net and ELMAH?

Python 2.6 introduced the [`str.format()`][1] method with a slightly different syntax from the existing `%` operator. Which is better and for what situations?

Python 3.6 has now introduced another string formatting format of string literals (aka &quot;f&quot; strings) via the syntax `f&quot;my string&quot;`. Is this formatting option better than the others?

1. The following uses each method and has the same outcome, so what is the difference?

    
        #!/usr/bin/python
        sub1 = &quot;python string!&quot;
        sub2 = &quot;an arg&quot;
    
        sub_a = &quot;i am a %s&quot; % sub1
        sub_b = &quot;i am a {0}&quot;.format(sub1)
        sub_c = f&quot;i am a {sub1}&quot;
    
        arg_a = &quot;with %(kwarg)s!&quot; % {&#39;kwarg&#39;:sub2}
        arg_b = &quot;with {kwarg}!&quot;.format(kwarg=sub2)
        arg_c = f&quot;with {sub2}!&quot;

        print(sub_a)    # &quot;i am a python string!&quot;
        print(sub_b)    # &quot;i am a python string!&quot;
        print(sub_c)    # &quot;i am a python string!&quot;

        print(arg_a)    # &quot;with an arg!&quot;
        print(arg_b)    # &quot;with an arg!&quot;
        print(arg_c)    # &quot;with an arg!&quot;

2. Furthermore when does string formatting occur in Python? For example, if my logging level is set to HIGH will I still take a hit for performing the following `%` operation? And if so, is there a way to avoid this?

        log.debug(&quot;some debug info: %s&quot; % some_info)


  [1]: https://docs.python.org/2/library/stdtypes.html#str.format

String formatting: % vs. .format vs. f-string literal

**C++** and **C#** both use the word `stream` to name many classes.
 
- **C++**: `iostream`, `istream`, `ostream`, `stringstream`, `ostream_iterator`, `istream_iterator`...
- **C#**:  `Stream`, `FileStream`,`MemoryStream`, `BufferedStream`...
 
So it made me curious to know, what does `stream` mean?
What are the characteristics of a `stream`?
When can I use this term to name my classes?
Is this limited to file I/O classes only?
 
Interestingly, **C** doesn’t use this word anywhere, as far as I know.

What does stream mean? What are its characteristics?

&lt;pre&gt;
    ostringstream s;

    s &amp;lt;&amp;lt; &quot;123&quot;;
    cout &amp;lt;&amp;lt; s.str().c_str() &amp;lt;&amp;lt; endl;

    // how to clear ostringstream here?
    s &amp;lt;&amp;lt; &quot;456&quot;;
    cout &amp;lt;&amp;lt; s.str().c_str() &amp;lt;&amp;lt; endl;
&lt;/pre&gt;

Output is:
&lt;pre&gt;
123
123456
&lt;/pre&gt;

I need:
&lt;pre&gt;
123
456
&lt;/pre&gt;

How can I reset ostringstream to get desired output?

How to clear ostringstream

I&#39;m not used to working with streams in Java - how do I create an `InputStream` from a `String`?

How does one create an InputStream from a String?

I have a list of objects and I need to save that somewhere in my computer. I have read some forums and I know that the object has to be `Serializable`. But it would be nice if I can get an example. For example if I have the following:

    [Serializable]
    public class SomeClass
    {
         public string someProperty { get; set; }
    }

    SomeClass object1 = new SomeClass { someProperty = &quot;someString&quot; };
    
But how can I store `object1` somewhere in my computer and later retrieve?
    

How to save/restore serializable object to/from file?

Say I have a function, for example the old favourite

    def factorial(n:Int) = (BigInt(1) /: (1 to n)) (_*_)

Now I want to find the biggest value of `n` for which `factorial(n)` fits in a Long. I could do 

    (1 to 100) takeWhile (factorial(_) &lt;= Long.MaxValue) last

This works, but the 100 is an arbitrary large number; what I really want on the left hand side is an infinite stream that keeps generating higher numbers until the `takeWhile` condition is met.

I&#39;ve come up with 

    val s = Stream.continually(1).zipWithIndex.map(p =&gt; p._1 + p._2)

but is there a better way?

(I&#39;m also aware I could get a solution recursively but that&#39;s not what I&#39;m looking for.)

Infinite streams in Scala

My error.log contains:

&gt;Request exceeded the limit of 10 internal redirects due to probable configuration error. Use &#39;LimitInternalRecursion&#39; to increase the limit if necessary. Use &#39;LogLevel debug&#39; to get a backtrace.

I replaced loglevel on apache config file:

`LogLevel debug`

After restarting, I&#39;m getting the same error message without what could be called &quot;a backtrace&quot;. As I understand there should be those 10 lines of redirects generated by mod_rewrite regex.

After searching all over the internet I&#39;ve found plenty of explanations of loglevel and mod_rewrite, but not a word of how to make loglevel debug work.

Any ideas?

How to enable loglevel debug on Apache2 server

Is it possible to do the following using ELMAH?

    logger.Log(&quot; something&quot;);

I&#39;m doing something like this:

    try 
    {
        // Code that might throw an exception 
    }
    catch(Exception ex)
    {
        // I need to log error here...
    }

This exception will not be automatically logged by ELMAH, because it was handled.



How to use ELMAH to manually log errors

I am using Apache/PHP/MySQL stack.  
Using as framework CakePHP. 

Every now and then I get a blank white page. I can&#39;t debug it through Cake, so I peek in the apache error.log and here&#39;s what I get:

    [Wed Oct 12 15:27:23 2011] [notice] child pid 3580 exit signal Segmentation fault (11)
    [Wed Oct 12 15:27:34 2011] [notice] child pid 3581 exit signal Segmentation fault (11)
    [Wed Oct 12 15:30:52 2011] [notice] child pid 3549 exit signal Segmentation fault (11)
    [Wed Oct 12 16:04:27 2011] [notice] child pid 3579 exit signal Segmentation fault (11)
    zend_mm_heap corrupted
    [Wed Oct 12 16:26:24 2011] [notice] child pid 3625 exit signal Segmentation fault (11)
    [Wed Oct 12 17:57:24 2011] [notice] child pid 3577 exit signal Segmentation fault (11)
    [Wed Oct 12 17:58:54 2011] [notice] child pid 3550 exit signal Segmentation fault (11)
    [Wed Oct 12 17:59:52 2011] [notice] child pid 3578 exit signal Segmentation fault (11)
    [Wed Oct 12 18:01:38 2011] [notice] child pid 3683 exit signal Segmentation fault (11)
    [Wed Oct 12 22:20:53 2011] [notice] child pid 3778 exit signal Segmentation fault (11)
    [Wed Oct 12 22:29:51 2011] [notice] child pid 3777 exit signal Segmentation fault (11)
    [Wed Oct 12 22:33:42 2011] [notice] child pid 3774 exit signal Segmentation fault (11)

What is this segmentation fault, and how can I fix it?

UPDATE:

    PHP Version 5.3.4, OSX local development
    Server version: Apache/2.2.17 (Unix)
    CakePhp: 1.3.10

&quot;[notice] child pid XXXX exit signal Segmentation fault (11)&quot; in apache error.log

Is there a way to make Python logging using the ``logging`` module automatically output things to stdout *in addition* to the log file where they are supposed to go? For example, I&#39;d like all calls to ``logger.warning``, ``logger.critical``, ``logger.error`` to go to their intended places but in addition always be copied to ``stdout``. This is to avoid duplicating messages like:

    mylogger.critical(&quot;something failed&quot;)
    print &quot;something failed&quot;


Making Python loggers output all messages to stdout in addition to log file

I&#39;ve created a small C# winforms application, as an added feature I was considering adding some form of error logging into it. Anyone have any suggestions for good ways to go about this? This is a feature I&#39;ve never looked into adding to previous projects, so I&#39;m open to suggestions from Developers who have more experience.

I was considering something along the lines of writing exceptions to a specified text file, or possibly a database table. This is an application that will be in use for a few months and then discarded when a larger product is finished.

Content Type	Original Author	Original Content on Stackoverflow
Question	user193476	View Question on Stackoverflow
Solution 1 - Logging	Jakob	View Answer on Stackoverflow
Solution 2 - Logging	Andrey Taptunov	View Answer on Stackoverflow

Should I log messages to stderr or stdout?

Logging Problem Overview

Logging Solutions

Solution 1 - Logging

Solution 2 - Logging

sorting a vector of structs

How to convert Dictionary<string, object> to Dictionary<string, string> in c#

Attributions