id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc	lang	patch	platform
1992	[NCI] callback sub parameter definition isn't unified with  callback definition in the C lib.	jimmy		"Hello,
   see https://github.com/parrot/parrot/blob/master/src/nci_test.c#-115 , there are two define here.


{{{
typedef void (*cb_C1_func)(const char*, void*);
PARROT_DYNEXT_EXPORT void nci_cb_C1(cb_C1_func, void*);
}}}


the callback is created by:

{{{
     cb_wrapped = new_callback cb, user_data, ""vtU""
}}}


which means it's first parameter is external_data, and the two is user_data. that is, the callback function should be defined as this one:

{{{
.sub _call_back
  .param string external_data
  .param pmc user_data
  print ""user data: ""
  print u
  print ""\n""
  print ""external data: ""
  print s
  print ""\n""
.end
}}}


but actually in t/pmc/nci.t, it's defined as:

{{{
.sub _call_back
  .param pmc user_data
  .param string external_data
  print ""user data: ""
  print u
  print ""\n""
  print ""external data: ""
  print s
  print ""\n""
.end

}}}


according to t/pmc/nci.t it seems that no matter user_data is the first parameter or two, the callback sub must be defined as:

{{{
.sub _call_back
  .param pmc user_data
  .param string external_data
.end
}}}


then I took a look at PDD16, and it's said user_data should be defined in the second parameter:


{{{
.sub _call_back
  .param string external_data
  .param pmc user_data
.end

}}}

which is right."	bug	new	normal		core	3.0.0	medium