exitCode -1 is error code after process closed

[creator4ever]

Function proc_close returns -1 when error occurred, success value can be equal or great then 0

[mikehaertl]

@creator4ever From PHP's manual on proc_close():

Returns the termination status of the process that was run. In case of an error then -1 is returned.

So it should return the termination status of the process. According to here only status 0 indicates a successful termination:

Every command returns an exit status (sometimes referred to as a return status or exit code). A successful command returns a 0, while an unsuccessful one returns a non-zero value that usually can be interpreted as an error code. Well-behaved UNIX commands, programs, and utilities return a 0 exit code upon successful completion, though there are some exceptions.

Looking at the comments on the proc_close() manual I agree though, that things can be a bit more complicated. So maybe there's some room for improvement, but the fix you propose would introduce new problems. Not sure about a better fix.

[mikehaertl]

As an example just look at the test case for executing a non existing command. With your change, execute() would now return success in this case, because the exit code is 127:

https://github.com/mikehaertl/php-shellcommand/blob/master/tests/CommandTest.php#L141

[glensc]

on linux (unixes) the process exit code is unsigned integer of size char (8 bits). so (signed)(char)-1 is converted as (unsigned)(char)127.

draw out the bits to visualize

[mikehaertl]

Should be fixed with #41.