[Swig-devel] [ swig-Bugs-3006404 ] PHP: std::string in callback method yields "Resource Id #8"

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Bugs item #3006404, was opened at 2010-05-24 12:25
Message generated for change (Comment added) made by wsfulton
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Category: php
Group: None
Status: Closed
Resolution: Fixed
Priority: 5
Private: No
Submitted By: t-Legiaw (t-legiaw)
Assigned to: Olly Betts (olly)
Summary: PHP: std::string in callback method yields "Resource Id #8"

Initial Comment:
Symptom: 

       wrong content if a std::string argument is passed to a PHP callback. Example:

                   std::string argument passed to callback: "Greetings from PHP" 
                   but an 'echo $msg' from inside the callback prints "Resource id #8"

                   (note: the number - in this case 8 varies)

However when the callback is called  directly from the PHP main script I am getting the expected result, for example

                      $callback = new PhpCallback();
                      $callback->run("PHP greetings without beeing used as a callback");

                      >>>  "PHP greetings without beeing used as a callback"


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>Comment By: William Fulton (wsfulton)
Date: 2010-05-26 05:39

Message:
Olly, this patch fixes the segfault. Probably the undefined behaviour
nature of this bug meant it sometimes worked, sometimes not. I thought the
php test-suite was 100% passing, but as this one was failing before the
patch was applied it might even have been erratic on my machine.

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Comment By: Olly Betts (olly)
Date: 2010-05-25 23:41

Message:
Yes, we're just missing a typemap.  Thanks for spotting that.

Fixed in SVN r12053.  Should be in the 2.0.0 release.

William: I'm not seeing that failure - all the php testsuite passes for
me, and trying your command does too...

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Comment By: William Fulton (wsfulton)
Date: 2010-05-25 18:27

Message:
The very latest svn contains a fix for RUNTOOL, so don't escape the space,
use:

~/swig/trunk/Examples/test-suite/php$ make director_string.cpptest
RUNTOOL="gdb --args"

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Comment By: William Fulton (wsfulton)
Date: 2010-05-25 17:42

Message:
This looks related to a failure in the php test-suite on my box. If you
run:

~/swig/trunk/Examples/test-suite/php$ make director_string.cpptest
RUNTOOL="gdb\ --args"

and run in gdb, I get the following stack trace:

(gdb) where
#0  0x082a4936 in ?? ()
#1  0x082bdd23 in ?? ()
#2  0x082cce92 in _zval_ptr_dtor ()
#3  0x082cecf4 in zend_call_function ()
#4  0x082cfe7c in call_user_function_ex ()
#5  0x082cfefb in call_user_function ()
#6  0x407dd586 in SwigDirector_A::get () from ./director_string.so
#7  0x407e1646 in A::get_first () from ./director_string.so
#8  0x407e0714 in _wrap_A_get_first () from ./director_string.so
#9  0x08314f03 in ?? ()
#10 0x0830039b in execute ()
#11 0x083147c6 in ?? ()
#12 0x0830039b in execute ()
#13 0x083147c6 in ?? ()
#14 0x0830039b in execute ()
#15 0x082daa00 in zend_execute_scripts ()
#16 0x0828f2da in php_execute_script ()
#17 0x0835f0a4 in main ()

SwigDirector_A::get () also returns a const std::string&.


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Comment By: t-Legiaw (t-legiaw)
Date: 2010-05-25 16:48

Message:
Update: I was able to fix the issue by using a directorin typemap (see also
attachement fixed-by-directorin-typemap.tar.gz )

<pre>
%typemap(directorin) const std::string & %{
  std::cout << $1_name << std::endl;
  ZVAL_STRINGL($input, $1_name.c_str(), $1_name.length(),  1);
%}
</pre>

and BTW: I am using PHP v5.3.2


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Comment By: t-Legiaw (t-legiaw)
Date: 2010-05-24 12:35

Message:
note: the same issue occurs when I change the callback parameter from
'std::string' to 'char *'

----------------------------------------------------------------------

Comment By: t-Legiaw (t-legiaw)
Date: 2010-05-24 12:27

Message:
Swig Version: 1.3.40
OS Environment: Ubuntu Lucid Lynx
g++ v4.4.3

----------------------------------------------------------------------

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