PHP return_var codes?

Question

I'm testing the php exec command:

http://php.net/exec

and I'm getting back a result code of 127.

My php code is:

<?  print "<br>executing 'hello':<br><b>"; exec ("hello", $output, $result); var_dump($output); print "<br>$result"; print "<br></b>end hello.";   print "<br><hr><br>";   print "<br>executing 'dir':<br><b>"; exec("dir", $output2, $result2); var_dump($output2); print "<br>$result2"; print "<br></b>end dir.";  ?> 

And the output is:

executing 'hello': array(0) { }  127 end hello.   executing 'dir': array(2) { [0]=> string(42) "bs1.jpg hello  index.htm ml1_1.jpg pp1.jpg" }  0 end dir. 

The php documentation (as far as I could find) says this:

return_var

If the return_var argument is present along with the output argument, then the return status of the executed command will be written to this variable.

...but does not have a list of output possibilities or a way to look them up.

Any suggestions?

Answer 1

Return codes can be a bit arbitrary. Basically though, any non-zero return value is an error. Here's a list of some common ones, but typically, unless you're working with a specific program, it's easier to just assume non-zero = some error was found, as opposed to trying to map a number of different programs to specific error codes.

Answer 2

Return code 127 means The specified procedure could not be found.

Assuming you are on Windows, Windows System Error Codes