How do I get PHP errors to display?

问题:

I have checked my PHP ini file (php.ini) and display_errors is set and also error reporting is E_ALL. I have restarted my Apache webserver.

I have even put these lines at the top of my script, and it doesn't even catch simple parse errors. For example, I declare variables with a "$" and I don't close statements";". But all my scripts show a blank page on these errors, but I want to actually see the errors in my browser output.

error_reporting(E_ALL);
ini_set('display_errors', 1);

What is left to do?

回答1:

This always works for me:

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

However, this doesn't make PHP to show parse errors - the only way to show those errors is to modify your php.ini with this line:

display_errors = on

(if you don't have access to php.ini, then putting this line in .htaccess might work too):

php_flag display_errors 1

回答2:

You can't catch parse errors when enabling error output at runtime, because it parses the file before actually executing anything (and since it encounters an error during this, it won't execute anything). You'll need to change the actual server configuration so that display_errors is on and the approriate error_reporting level is used. If you don't have access to php.ini, you may be able to use .htaccess or similar, depending on the server.

This question may provide additional info.

回答3:

Inside your php.ini:

display_errors = on

Then restart your web server.

回答4:

To display all errors you need to:

1. Have these lines in the PHP script you're calling from the browser (typically index.php):

error_reporting(E_ALL);
ini_set('display_errors', '1');

2.(a) Make sure that this script has no syntax errors

—or—

2.(b) Set display_errors = On in your php.ini

Otherwise, it can't even run those 2 lines!

You can check for syntax errors in your script by running (at the command line):

php -l index.php

If you include the script from another PHP script then it will display syntax errors in the included script. For example:

index.php

error_reporting(E_ALL);
ini_set('display_errors', '1');

// Any syntax errors here will result in a blank screen in the browser

include 'my_script.php';

my_script.php

adjfkj // This syntax error will be displayed in the browser

回答5:

Some web hosting providers allow you to change PHP parameters in the .htaccess file.

You can add the following line:

php_value display_errors 1

I had the same issue as yours and this solution fixed it.

回答6:

You might find all of the settings for "error reporting" or "display errors" do not appear to work in PHP 7. That is because error handling has changed. Try this instead:

try{
     // Your code
} 
catch(Error $e) {
    $trace = $e->getTrace();
    echo $e->getMessage().' in '.$e->getFile().' on line '.$e->getLine().' called from '.$trace[0]['file'].' on line '.$trace[0]['line'];
}

Or, to catch exceptions and errors in one go (this is not backward compatible with PHP 5):

try{
     // Your code
} 
catch(Throwable $e) {
    $trace = $e->getTrace();
    echo $e->getMessage().' in '.$e->getFile().' on line '.$e->getLine().' called from '.$trace[0]['file'].' on line '.$trace[0]['line'];
}

回答7:

This will work:

<?php
     error_reporting(E_ALL);
     ini_set('display_errors', 1);    
?>

回答8:

Use:

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

This is the best way to write it, but a syntax error gives blank output, so use the console to check for syntax errors. The best way to debug PHP code is to use the console; run the following:

php -l phpfilename.php

回答9:

Set this in your index.php file:

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

回答10:

Create a file called php.ini in the folder where your PHP file resides.

Inside php.ini add the following code (I am giving an simple error showing code):

display_errors = on

display_startup_errors = on

回答11:

Here is a PHP script:

<?php
    ini_set("display_startup_errors", 1);
    ini_set("display_errors", 1);

    /* Reports for either E_ERROR | E_WARNING | E_NOTICE  | Any Error*/
    error_reporting(E_ALL);

    echo(abc); /* Notice: abc is an undefined constant */
?>

For a more detailed explanation of PHP errors, visit PHP Error - error_reporting().

回答12:

When using PHP as an Apache module, we can a change the configuration settings using directives in Apache configuration files (e.g. httpd.conf) and .htaccess files. You will need “AllowOverride Options” or “AllowOverride All” privileges to do so.

Check this

http://funbird.co.uk/blog/tech-articals/linux-tech-articals/enabling-error-display-php-via-htaccess

回答13:

If, despite following all of the above answers (or you can't edit your php.ini file), you still can't get an error message, try making a new PHP file that enables error reporting and then include the problem file. eg:

error_reporting(E_ALL);
ini_set('display_errors', 1);
require_once('problem_file.php');

Despite having everything set properly in my php.ini file, this was the only way I could catch a namespace error. My exact scenario was:

//file1.php
namespace a\b;
class x {
    ...
}

//file2.php
namespace c\d;
use c\d\x; //Dies because it's not sure which 'x' class to use
class x {
    ...
}

回答14:

I would usually go with the following code in my plain PHP projects.

if(!defined('ENVIRONMENT')){
    define('ENVIRONMENT', 'DEVELOPMENT');
}

$base_url = null;

if (defined('ENVIRONMENT'))
{
    switch (ENVIRONMENT)
    {
        case 'DEVELOPMENT':
            $base_url = 'http://localhost/product/';
            ini_set('display_errors', 1);
            ini_set('display_startup_errors', 1);
            error_reporting(E_ALL|E_STRICT);
            break;

        case 'PRODUCTION':
            $base_url = 'Production URL'; /* https://google.com */
            error_reporting(0);
            /* Mechanism to log errors */
            break;

        default:
            exit('The application environment is not set correctly.');
    }
}

回答15:

If you somehow find yourself in a situation where you can't modifiy the setting via php.ini or .htaccess you're out of luck for displaying errors when your PHP scripts contain parse errors. You'd then have to resolve to linting the files on the command line like this:

find . -name '*.php' -type f -print0 | xargs -0 -n1 -P8 php -l | grep -v "No syntax errors"

If your host is so locked down that it does not allow changing the value via php.ini or .htaccess, it may also disallow changing the value via ini_set. You can check that with the following PHP script:

<?php
if( !ini_set( 'display_errors', 1 ) ) {
  echo "display_errors cannot be set.";
} else {
  echo "changing display_errors via script is possible.";
}

回答16:

As we are now running PHP 7, answers given here are not correct any more. The only one still OK is the one from Frank Forte, as he talks about PHP 7.

On the other side, rather than trying to catch errors with a try/catch you can use a trick: use include.

Here three pieces of code:

File: tst1.php

<?php
    error_reporting(E_ALL);
    ini_set('display_errors', 'On');
    // Missing " and ;
    echo "Testing
?>

Running this in PHP 7 will show nothing.

Now, try this:

File: tst2.php

<?php
    error_reporting(E_ALL);
    ini_set('display_errors', 'On');
    include ("tst3.php");
?>

File: tst3.php

<?php
    // Missing " and ;
    echo "Testing
?>

Now run tst2 which sets the error reporting, and then include tst3. You will see:

Parse error: syntax error, unexpected end of file, expecting variable (T_VARIABLE) or ${ (T_DOLLAR_OPEN_CURLY_BRACES) or {$ (T_CURLY_OPEN) in tst3.php on line 4

回答17:

You can do something like below:

Set the below parameters in your main index file:

    ini_set('display_errors', 1);
    ini_set('display_startup_errors', 1);

Then based on your requirement you can choose which you want to show:

For all errors, warnings and notices:

    error_reporting(E_ALL); OR error_reporting(-1);

For all errors:

    error_reporting(E_ERROR);

For all warnings:

    error_reporting(E_WARNING);

For all notices:

    error_reporting(E_NOTICE);

For more information, check here.

回答18:

You can add your own custom error handler, which can provide extra debug information. Furthermore, you can set it up to send you the information via email.

function ERR_HANDLER($errno, $errstr, $errfile, $errline){
    $msg = "<b>Something bad happened.</b> [$errno] $errstr <br><br>
    <b>File:</b> $errfile <br>
    <b>Line:</b> $errline <br>
    <pre>".json_encode(debug_backtrace(), JSON_PRETTY_PRINT)."</pre> <br>";

    echo $msg;

    return false;
}

function EXC_HANDLER($exception){
    ERR_HANDLER(0, $exception->getMessage(), $exception->getFile(), $exception->getLine());
}

function shutDownFunction() {
    $error = error_get_last();
    if ($error["type"] == 1) {
        ERR_HANDLER($error["type"], $error["message"], $error["file"], $error["line"]);
    }
}

set_error_handler ("ERR_HANDLER", E_ALL & ~E_NOTICE & ~E_STRICT & ~E_DEPRECATED);
register_shutdown_function("shutdownFunction");
set_exception_handler("EXC_HANDLER");

回答19:

This code on top should work:

error_reporting(E_ALL);

However, try to edit the code on the phone in the file:

error_reporting =on

回答20:

The best/easy/fast solution that you can use if it's a quick debugging, is to surround your code with catching exceptions. That's what I'm doing when I want to check something fast in production.

try {
    // Page code
}
catch (Exception $e) {
    echo 'Caught exception: ',  $e->getMessage(), "\n";
}

回答21:

Just write:

error_reporting(-1);

回答22:

That's what I learnt. In the PHP.INI file,

error_reporting = E_ALL
display_errors = On

回答23:

    <?php
    // Turn off error reporting
    error_reporting(0);

    // Report runtime errors
    error_reporting(E_ERROR | E_WARNING | E_PARSE);

    // Report all errors
    error_reporting(E_ALL);

    // Same as error_reporting(E_ALL);
    ini_set("error_reporting", E_ALL);

    // Report all errors except E_NOTICE
    error_reporting(E_ALL & ~E_NOTICE);
    ?>

While your site is live, the php.ini file should have display_errors disabled for security reasons. However, for the development environment, display_errors can be enabled for troubleshooting.

回答24:

You can do this by changing the php.ini file and add the following

display_errors = on
display_startup_errors = on

OR you can also use the following code as this always works for me

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

回答25:

If you have Xdebug installed you can override every setting by setting:

xdebug.force_display_errors = 1;
xdebug.force_error_reporting = -1;

force_display_errors

Type: int, Default value: 0, Introduced in Xdebug >= 2.3 If this setting is set to 1 then errors will always be displayed, no matter what the setting of PHP's display_errors is.

force_error_reporting

Type: int, Default value: 0, Introduced in Xdebug >= 2.3 This setting is a bitmask, like error_reporting. This bitmask will be logically ORed with the bitmask represented by error_reporting to dermine which errors should be displayed. This setting can only be made in php.ini and allows you to force certain errors from being shown no matter what an application does with ini_set().

回答26:

You might want to use this code:

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);

回答27:

Report all errors except E_NOTICE

error_reporting(E_ALL & ~E_NOTICE);

Display all PHP errors

error_reporting(E_ALL);  or ini_set('error_reporting', E_ALL);

Turn off all error reporting

error_reporting(0);

回答28:

Other than php.ini and ini_set() function in php script you can do this same thing with .htaccess and httpd.conf directives shown below. Some hosting providers allow set php settings through .htaccess and httpd.conf.

#hide php errors

php_flag display_startup_errors ON

php_flag display_errors ON

php_flag html_errors ON

php_flag log_errors on

php_flag ignore_repeated_errors off

php_flag ignore_repeated_source off

php_flag report_memleaks on

php_flag track_errors on

php_value docref_root 0

php_value docref_ext 0

php_value error_log /home/path/public_html/domain/PHP_errors.log

php_value error_reporting 999999999

php_value error_reporting -1

php_value log_errors_max_len 0

Order allow,deny

Deny from all

Satisfy All

回答29:

It if is in command line, you can run php with -ddisplay_errors=1 to override the setting in php.ini:

php -ddisplay_errors=1 script.php

回答30:

In unix cli, it's very practical to redirect only errors to a file:

./script 2> errors.log

Then from another shell, for live changes:

tail -f errors.log

or simply

watch cat errors.log