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What is the use of the # symbol in PHP?
(11 answers)
Closed 9 years ago.
What is the meaning of ##variable in php ?
$fix=##parts;
# is used to suppress any errors that may occur on this line of the code
http://php.net/manual/en/language.operators.errorcontrol.php
When prepended to an expression in PHP, any error messages that might
be generated by that expression will be ignored.
I would not recommend using it at all because this may result in failure of noticing some important error/warning and make debugging a havoc. On a production environment use error_reporting setting that will prevent any errors or warning from showing up while on a development server I would recommend to turn on any error reporting
PHP supports one error control operator: the at sign (#). When
prepended to an expression in PHP, any error messages that might be
generated by that expression will be ignored.
Link : PHP.net explanation
The #operator turns off error handling.
Related
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Reference Guide: What does this symbol mean in PHP? (PHP Syntax)
(24 answers)
Closed 9 years ago.
I found this tutorial on making a try it editor for a website.
I understood everything in the code except the # in the result.php:
Result.php
<?php
$myCode = #$_REQUEST["code"];
print $myCode ;
?>
Also I tried removing it from the code and nothing changed, so what does it do?
# is a PHP error control operator
PHP supports one error control operator: the at sign (#). When prepended to an expression in PHP, any error messages that might be generated by that expression will be ignored
Reference
http://php.net/manual/en/language.operators.errorcontrol.php
Example
<?php
/* Intentional file error */
$my_file = #file ('non_existent_file') or
die ("Failed opening file: error was '$php_errormsg'");
// this works for any expression, not just functions:
$value = #$cache[$key];
// will not issue a notice if the index $key doesn't exist.
?>
It ignores/suppresses error messages - see Error Control Operators in the PHP manual.
PHP supports one error control operator: the at sign (#). When prepended to an expression in PHP, any error messages that might be generated by that expression will be ignored.
If you have set a custom error handler function with set_error_handler() then it will still get called, but this custom error handler can (and should) call error_reporting() which will return 0 when the call that triggered the error was preceded by an #.
so any error in $myCode = #$_REQUEST["code"]; will be ignored.
This question already has answers here:
'At' symbol before variable name in PHP: #$_POST
(5 answers)
Closed 9 years ago.
Can you please tell me the difference between
$variable and #$variable in php
<?php
curl function abc
{
get information of url and return information string
}
$html=abc();
$doc=DOMDocument();
#$doc->LoadHTML($html);
?>
here if we take normal variable it gives error why its so
and whats the difference
A # before a function call means "suppress warnings".
So, #$doc->LoadHTML($html); suppresses warnings from the method call (LoadHTML()).
In general this is a bad idea, because the warnings mean you are doing something wrong, and you would better fix that instead of playing deaf.
The # operator tells the compiler to ignore the error that PHP could give, its advised not to use it.
Suppress warning when accessing that property, if for instance $html was undefined then no error is displayed, see http://davidwalsh.name/suppress-php-errors-warnings
# is called Error Control Operator, it can be prepended before expression to disable error reporting for that expression.
Please see this post for more information: Suppress error with # operator in PHP
This question already has answers here:
What does # mean in PHP? [duplicate]
(5 answers)
Closed 8 years ago.
I am a newbie in PHP.
I do not know the meaning of #, for example:
$key = #$_REQUEST['key'];
I have searched in google but can not find anything.
Some help me! Please !
The # symbol tells the function to fail silently instead of dumping some sort of error message. It is listed under error control operators in the PHP manual.
It suppresses any errors that the line would normally produce. In this case if the key doesn't exist, an error will occur but the error text will be silenced.
It suppresses errors and warnings.
You've found the error control operator!
It suppresses warnings in PHP. In that example it could be used to suppress and undefined index warning, if $_REQUEST['key'] doesn't exist. It's usually better practice to write:
$key = isset($_REQUEST['key']) ? $_REQUEST['key'] : 'default value for key here';
This question already has answers here:
Closed 12 years ago.
Possible Duplicates:
Reference - What does this symbol mean in PHP?
What does # mean in PHP?
I have a line in my code which looks like this:
#mysql_select_db($dbname) or die( "Error: Unable to select database");
It works, but I want to know what the # does and why it is there.
The # symbol suppresses any errors and notices for the expression it precedes.
See this reference: PHP Error Control Operators
PHP supports one error control
operator: the at sign (#). When
prepended to an expression in PHP, any
error messages that might be generated
by that expression will be ignored.
In this case, the # will suppress the regular PHP database connection error (which may contain sensitive information). In case of a connection error, the "or die" part will be executed, failing with a generic error message. The line is probably copied from a "quick and dirty" example.
Using the error suppression operator # is considered bad style, especially when other forms of error handling are missing. It complicates debugging - how can you find out about in error without any indication that it occured? In a production system it's better to log all errors to a file and suppress the rendering of errors on the page. You could do that in the php.ini file or (if you are on a shared host and not allowed to make config changes) with the following code.
ini_set('display_errors', false);
ini_set('log_errors', true);
ini_set('error_log', '/var/log/apache/php-errors.log');
It suppresses all error output. Generally, you shouldn't use it unless you have a good reason. I don't know why it is used in the example you posted, or why die() is used. The error should be caught and processed accordingly. The select may fail for a number of reasons, some perhaps recoverable. Like no connection to the database established.
This question already has answers here:
Closed 13 years ago.
Possible Duplicate:
What is the use of # symbol in php?
I like to know the purpose and meaning of # in php codes.
For instance, #umask or #ini_set. What's the difference without # and with #?
PHP's error suppress operator used to suppress error messages.
SideNote: Avoid it as much as you can, also it slows down performance heavily and not allowed to be used in ini_get and ini_set functions in future php versions.
"Swallow an error", continue despite an error occuring. An non-critical operation augmented with # will not abort script execution.
# symbol is an error control operator check out manual here