debugging - Reference - What does this error mean in PHP? -

What's this?

There are many answers about warnings, errors and notices, while programming PHP and no clue how to fix it is also a community wiki, so everyone should add this list and keep it Has been invited to take.

Why is this?

The questions are often the same as the stack overflow or the root cause of those questions is always the same, so the answers to those questions usually repeat them and then show the OP which lines are special The case is to change. These answers do not add any value to the site because they only apply to the special codes of OP. Other users with the same error can not easily remove this solution because they are very local. It is sad, because once you understand the root cause, fixing the error is trivial, therefore, a general way to implement this list Attempts to explain the solution.

What should I do here?

If your question has been marked as a duplicate of this, please apply your error message below and to correct your code. Answers are usually more in the investigation and links, If this should not be made clear from the general answer.

If you want to contribute, please add your "favorite" error message, warning or notice, reply to a copy, a brief description that means it (even if it is only your Feel free to improve any existing answer, except that the list of possible solutions or debugging approaches and current Q & A are worth the value, highlighting the conditions on the manual page).

List

• (also known as White Page / Screen of Death )
• aka
  aka
  (or similar variations)
• <
• [context]

• See also

  • Warning: header information can not be modified - headers already sent May include

    when your script tries to send HTTP headers client, but first came to the same output, the resulting header had already been sent to the client.

    This is one and it will not stop the script.

    A typical example would be a template file like this:

      & lt; Html & gt; & Lt ;? Php session_start (); ? & Gt; & Lt; Head & gt; & Lt; Title & gt; My page & lt; / Title & gt; & Lt; / Html & gt; ...   
      session_start ()  function will attempt to send the header to the customer with the session cookie. But PHP has already sent headers when it comes to  & lt; Html & gt;  element wrote you have to move  session_start ()  to the top.  
     You can solve this by going through the lines  before  triggering warning and check where it produces. Prior to that code, send any header sender code.  
     PHP closing ? & Gt;  Once the unexpected outputs are new lines, do i ? & Gt;  is considered to be a standard practice, when it is the last thing in the file similarly, there is another common reason for this warning when the opening   has an empty space, line or invisible character, due to which the webserver has to send headers and white space / new line. Starting PHP parsing will not be able to submit any header.  
     If your file contains more than one  & lt ;? Php ...? & Gt;  The code is block, so you should not have any space between them. (Note: You may have multiple blocks if you had code that was automatically created)  
     Also make sure that you do not have any code byte order, for example, when the script With encoding UTF-8 BOM.  
     Related questions:  
     
      
      
      
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