debug_backtrace and FILE/LINE indices

Hi all,

I've been using debug_backtrace() for a while to provide stack traces
for a custom logging function. Today was the first time I've got the
following error:

"Notice: Undefined index: file in E:\webroot\lib\errors.php on line
341

Notice: Undefined index: line in E:\webroot\lib\errors.php on line
341"

related to the following code:

$vDebug = debug_backtrace();
$vFiles = array();
for ($i=0;$i<count($vDebug);$i++) {
// skip the first one, since it's always this func
if ($i==0) { continue; }
$aFile = $vDebug[$i];
var_dump($aFile);
$vFiles[] = '('.basename($aFile['file']).':'.
$aFile['line'].')';
} // for
return implode(',',$vFiles);

I checked the PHP documentation for this function, and to my surprise
found that:

"The *possible* returned elements are as follows:", ie: 'file' and
'line' wont always be returned. When are these elements returned, so
that I can make the function do something useful when file/line isn't
returned?

Thanks

Taras

Also sprach Taras_96:

> $vDebug = debug_backtrace();
> $vFiles = array();
> for ($i=0;$i<count($vDebug);$i++) {
> // skip the first one, since it's always this func
> if ($i==0) { continue; }
> $aFile = $vDebug[$i];
> var_dump($aFile);
> $vFiles[] = '('.basename($aFile['file']).':'.
> $aFile['line'].')';
> } // for
> return implode(',',$vFiles);
>
> I checked the PHP documentation for this function, and to my surprise
> found that:
>
> "The *possible* returned elements are as follows:", ie: 'file' and
> 'line' wont always be returned. When are these elements returned, so
> that I can make the function do something useful when file/line isn't
> returned?

A workaround: If 'file' and 'line' are not returned, use the respective
values from the next entry in the backtrace array. Here's what I use:

$aTrace = debug_backtrace();
// Loop backwards (!) through array
for ( $sFile = '', $iLine = 0, $i = count( $aTrace ); $i--; )
{
// Make sure all fields are set
$aTrace[$i]
= array_merge(
array(
'function' => '',
'type' => '',
'class' => '',
'object' => array(),
'args' => array(),
'file' => $sFile,
'line' => $iLine
),
$aTrace[$i]
);

// Add this for convenience
$aTrace[$i]['call']
= $aTrace[$i]['class']
. $aTrace[$i]['type']
. $aTrace[$i]['function'];

// Missing file or line? Copy from previous item
$sFile = $aTrace[$i]['file'];
$iLine = $aTrace[$i]['line'];
}

// Remove first item ("this function")
array_shift( $aTrace );

This way, all possible fields are set to useful values. If you're only
interested in file and line, you can optimize the code of course.

Greetings,
Thomas

Thanks Thomans, I'll try out your suggestion and see how it goes :).

Taras

On Apr 25, 5:01 am, "Thomas Mlynarczyk" <tho...@mlynarczyk-
webdesign.de> wrote:
> Also sprach Taras_96:
>
>
>
> > $vDebug = debug_backtrace();
> > $vFiles = array();
> > for ($i=0;$i<count($vDebug);$i++) {
> > // skip the first one, since it's always this func
> > if ($i==0) { continue; }
> > $aFile = $vDebug[$i];
> > var_dump($aFile);
> > $vFiles[] = '('.basename($aFile['file']).':'.
> > $aFile['line'].')';
> > } // for
> > return implode(',',$vFiles);
>
> > I checked the PHP documentation for this function, and to my surprise
> > found that:
>
> > "The *possible* returned elements are as follows:", ie: 'file' and
> > 'line' wont always be returned. When are these elements returned, so
> > that I can make the function do something useful when file/line isn't
> > returned?
>
> A workaround: If 'file' and 'line' are not returned, use the respective
> values from the next entry in the backtrace array. Here's what I use:
>
> $aTrace = debug_backtrace();
> // Loop backwards (!) through array
> for ( $sFile = '', $iLine = 0, $i = count( $aTrace ); $i--; )
> {
> // Make sure all fields are set
> $aTrace[$i]
> = array_merge(
> array(
> 'function' => '',
> 'type' => '',
> 'class' => '',
> 'object' => array(),
> 'args' => array(),
> 'file' => $sFile,
> 'line' => $iLine
> ),
> $aTrace[$i]
> );
>
> // Add this for convenience
> $aTrace[$i]['call']
> = $aTrace[$i]['class']
> . $aTrace[$i]['type']
> . $aTrace[$i]['function'];
>
> // Missing file or line? Copy from previous item
> $sFile = $aTrace[$i]['file'];
> $iLine = $aTrace[$i]['line'];
> }
>
> // Remove first item ("this function")
> array_shift( $aTrace );
>
> This way, all possible fields are set to useful values. If you're only
> interested in file and line, you can optimize the code of course.
>
> Greetings,
> Thomas