How to return a line number in a PHP script

Question

Is it possible for a PHP script to return a line number in which some command is called? I'm having trouble describing what I want so maybe an example.

I have PHP code that calls MySQL on many occasions. In line 49 is:

$resultDevice = mysql_query("Some SQL;") or die ("MySQL-Error in settingsU line 49: " . mysql_error());

The text "line 49" I wrote manually. Is it possible to get this number "49" updated if I change my code? It would make my life easier to debug. Of course I can put some other line-specific text into die, but lines are much easier to find in a text-editor.

Don't Panic · Accepted Answer · 2018-08-08 17:50:37Z

132

You can use the magic constant __LINE__ for this.

echo  __LINE__;

will show the line number where that statement is in the file.

edited Aug 8, 2018 at 17:50

Don't Panic

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answered Mar 28, 2013 at 14:33

Nobody

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1 Comment

Kris_R Over a year ago

thanks a lot -- it led me directly to some other nice constants.

Elikill58 · Accepted Answer · 2025-01-07 13:01:21Z

10

if you want a trace you can use (For PHP 4 >= 4.3.0):

function error_report_function($error) {
   $dbgt = debug_backtrace();
   return "$error in {$dbgt[1]['file']} on line {$dbgt[1]['line']}";
}

You can use debug_backtrace for this or else always pass the line (with __LINE__)

edited Jan 7 at 13:01

Elikill58

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answered Mar 29, 2013 at 2:06

internals-in

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Comments

janisch · Accepted Answer · 2021-11-19 07:58:25Z

1

You could use something like this:

function throwSQLError($file, $line, $error) {
    return "MySQL-Error in " . $file . " on line " . $line . ": " . $error;
}

$result = mysql_query("Some SQL;") or die (throwSQLError(__FILE__, __LINE__, mysql_error()));

This gives you a dynamic function to throw the error you can use multiple times.

Untested, just written in raw editor.

edited Nov 19, 2021 at 7:58

answered Sep 30, 2020 at 6:06

janisch

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