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Re: JNI and GetFieldID

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Steven Simpson wrote:
> On 08/09/13 11:29, Borneq wrote:
> > Inside StateProc I can call my_callback function, and ACEListProc will
> > be called inside native function. Native function can store env and
> > others parameters. But how within StateProc refer to this env and
> > other parameters?
>
> It's a bugger, isn't it?!

I think what you (plural) are looking for is the GetEnv() function, or the 
(JavaVM::GetEnv() method).  That will return the correct JNIEnv to use in 
whatever context you call it.  If there already is a JNIEnv that can be validly 
used in that context then the operation is cheap.  If not then the operation is 
a bit more expensive, but necessary and so unavoidable.

If you are dealing with callbacks that might not happen on a thread that's 
known to Java (improbable in this case) then you'd better look into 
AttachCurrentThread() and DetachCurrentThread() too.

If the main program is a Java program (rather than a C/C++/whatever program 
that uses Java via JNI) then you won't naturally have a reference to a JavaVM. 
You can find that from any handy JNIEnv with GetJavaVM().  The JavaVM is a 
globally shared, and unique, object, so it can be treated as threadsafe (there 
may be documented exceptions to that -- I no longer remember clearly), and so 
it's OK to put a reference to it into some shared global variable at the C/C++ 
level.

    -- chris 

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Thread

JNI and GetFieldID "Borneq" <borneq@antyspam.hidden.pl> - 2013-09-05 17:05 +0200
  Re: JNI and GetFieldID Mark <i@dontgetlotsofspamanymore.invalid> - 2013-09-06 10:25 +0100
  Re: JNI and GetFieldID Steven Simpson <ss@domain.invalid> - 2013-09-06 16:36 +0300
    Re: JNI and GetFieldID "Borneq" <borneq@antyspam.hidden.pl> - 2013-09-06 18:53 +0200
      Re: JNI and GetFieldID "Borneq" <borneq@antyspam.hidden.pl> - 2013-09-06 20:44 +0200
        Re: JNI and GetFieldID Steven Simpson <ss@domain.invalid> - 2013-09-06 22:34 +0300
          Re: JNI and GetFieldID "Borneq" <borneq@antyspam.hidden.pl> - 2013-09-06 23:06 +0200
      Re: JNI and GetFieldID "Borneq" <borneq@antyspam.hidden.pl> - 2013-09-07 22:27 +0200
        Re: JNI and GetFieldID Steven Simpson <ss@domain.invalid> - 2013-09-08 10:24 +0100
          Re: JNI and GetFieldID "Borneq" <borneq@antyspam.hidden.pl> - 2013-09-08 12:29 +0200
            Re: JNI and GetFieldID "Borneq" <borneq@antyspam.hidden.pl> - 2013-09-08 22:45 +0200
            Re: JNI and GetFieldID Steven Simpson <ss@domain.invalid> - 2013-09-13 13:31 +0100
              Re: JNI and GetFieldID "Borneq" <borneq@antyspam.hidden.pl> - 2013-09-14 18:50 +0200
              Re: JNI and GetFieldID "Chris Uppal" <chris.uppal@metagnostic.REMOVE-THIS.org> - 2013-09-19 15:02 +0100

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