Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!romp!auschs!awdprime!longhorn.austin.ibm.com!jason
From: jason@longhorn.austin.ibm.com (Jason Lowdermilk)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: Need help accessing MathTrans library from Task
Message-ID: <5847@awdprime.UUCP>
Date: 12 Mar 91 17:23:47 GMT
References: <5778@awdprime.UUCP> <29024.27db9dce@kuhub.cc.ukans.edu>
Sender: news@awdprime.UUCP
Distribution: na
Organization: IBM AWD, Austin
Lines: 30

In article <29024.27db9dce@kuhub.cc.ukans.edu> markv@kuhub.cc.ukans.edu writes:
>> I'm having a problem accessing the transcendental math library from a 
>> "child task" created with CreateTask, in particular the sqrt function.
>
>A task can call MathTrans library.  It cannot always call
>OpenLibrary("mathtrans.library",34L); because if the library is not in
>memory, then Exec will call LoadSeg() to get the library in memory,
>which is guarenteed to be a one way trip to la-la land if it isn't a process.
>
>So, the parent of the child needs to OpenLibrary() so that the library
>is in memory.  Then the child can get the base from the parent
>(easy to do if child is a function in the parent and they share global
>data), otherwise the child can call OpenLibrary() as long as the
>parent holds mathtrans.library open to keep it in memory.
>

The parent process opens the mathtrans library prior to creating the child.
The parent also calls sqrt() several times before creating the child. Sqrt 
is the the only transcendental function I am using, although I can
duplicate the problem by calling some other function such as sin().
I have worked around this problem by writing my own sqrt routine as a 
function (in fact it is several times faster than the system sqrt,
albeit less accurate), but I am still curious why this doesn't work. I can 
put together a minimal code example that illustrates this and post it tomorrow. 

-- 
Jason Lowdermilk
  internet: jason@longhorn.austin.ibm.com
  UUCP: @cs.utexas.edu:ibmchs!auschs!longhorn.austin.ibm.com!jason
  VNET: LOWDERMI@DALVM41B