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Closed 11 years ago.
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Reference - What does this symbol mean in PHP?
I've seen in PHP some variables that are set like this:
$var = #$something;
Or functions set like this:
$var = &my_function();
What effect do the # and the & have?
You have them backwards. &$variable means "a reference to this variable." #my_function() means "call this function and suppress any errors or warnings that it produces."
# means "don't report errors"
& means "take a reference to the following variable instead of copying its value"
# operator in php is used to ignore errors in that statement.
Manual: http://www.php.net/manual/en/language.operators.errorcontrol.php
& is reference operator.
Manual: http://www.php.net/manual/en/language.references.whatdo.php
# causes to hide all errors. In case of variables, it might be E_NOTICE informing about variable not existing.
The &my_function(); is invalid - & is normally used for references, it doesn't nothing in this case.
Related
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
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Reference Guide: What does this symbol mean in PHP? (PHP Syntax)
(24 answers)
Closed 9 years ago.
I'm learning object oriented php.
I've come across some code I don't fully understand.
This code is within a class.
1) code that uses #.
For example:
$this->image = #imagecreatefromgif($filename);
Can some one explain the uses of #.
2)
Also it looks like the script is declaring variables in a way i'm not used to (the $var way).
For example:
$this->ext = $size['mime'];
$ext is not declared before this code is used, but it used after it. Does this create an $ext variable within the object?
Thanks guys!!
The # will suppress errors so that no errors will be shown for that expression.
http://php.net/manual/en/language.operators.errorcontrol.php
# is php's error suppression operator you should never use it
You should handle error instead ignoring and advantage would be you will get long notice which is helpful to debug too
And worst case would be below as described in manual
Currently the "#" error-control operator prefix will even disable error reporting for critical errors that will terminate script execution. Among other things, this means that if you use "#" to suppress errors from a certain function and either it isn't available or has been mistyped, the script will die right there with no indication as to why.
# Means "Suppress warning when calling this function".
This question already has answers here:
Closed 10 years ago.
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What is the use of # symbol in php?
PHP functions and #functions
What does the “#” symbol do in SQL?
Often when looking through online resources / questions including code on this website, I often come across the '#' operator.
In the PHP code I see, the # operator generally comes before a method such as #fread(). However, by the looks of the code, it wouldn't have actually made a difference whether or not fread() was called with or without the '#' in front of the method.
In the MySQL code, the # operator generally comes before a column/field name. I believe that the # is used to access a default variable instantiated at some point manually by the user, alike to an env variable in PHP.
Please can you tell me if my assumptions are correct, and if not, when and why the '#' sign or operator should in fact be used?
Thanks,
Max.
In PHP it means suppress any notices/warnings raised by this function eg mail() will throw an error when it fails to send. You can do
$Success = #mail(...)
To suppress the error and handle success/failure yourself. See the Error Control Operator page for more information.
In MySQL, # is used to prefix user-defined variables
In PHP the at sign (#) denotes that any error messages that might be generated by that expression will be ignored.
In MySQL the # before a name denotes a local, user-defined variable.
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 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