robby@nuchat.sccsi.com (Robert Oliver Jr.) (06/12/91)
Hi,
Has anyone out there been over 65520 in stack and had the program work?
I need to know how to get over the stack limit. Sence the pointer will not
work right. Is there something wrong with this statement ?
Testing : Array[1..220] of ^Test; {Test is a Type Record}
and calling the data with Testing[Index]^.Whois ???
Is there something wrong with this ?
Thanks,
Robert Oliver dm2368@eecs1.eecs.usma.edu (Fichten Mark CPT) (06/13/91)
Robert Oliver writes: > Hi, > Has anyone out there been over 65520 in stack and had the program work? > I need to know how to get over the stack limit. Sence the pointer will not > work right. Is there something wrong with this statement ? > > Testing : Array[1..220] of ^Test; {Test is a Type Record} > > and calling the data with Testing[Index]^.Whois ??? > > Is there something wrong with this ? This will work fine IF you 'attach' a record to each element of the array like this: for i:=1 to 220 do begin New(Testing[i]); { Initialize the fields of your record here... } Testing[i]^.Next := nil; end; This loop will set you up a structure like the following: ARRAY Records TESTING |-------| --------- | 1 |----->| |--nil |-------| --------- --------- | 2 |--------------->| |--nil |-------| --------- | . | | . | | . | |-------| --------- | 218 |----->| |--nil |-------| --------- --------- | 219 |--------------->| |--nil |-------| --------- --------- | 220 |----->| |--nil |-------| --------- The loop allocates memory OFF OF THE HEAP, NOT THE STACK. Assuming that you have not decreased the size of the heap with a compiler directive, or used up most of your heap, this should work fine. Remember to deallocate all the memory if you are finished with the array and the program does other things. A loop like the following will work: for i:=1 to 220 do Dispose(Testing[i]); This will free all the memory ONLY if you have not 'attached' any other nodes on the ends of the records. I'll leave any more complex disposal loop to you! Hope this helps. ____________________________________________________________________________ CPT Mark Fichten | INTERNET: fichten@eecs1.eecs.usma.edu | Captain U.S. Army | @trotter.edu:dm2368@eecs1.eecs.usma.edu | Work: (914) 938-5580 | USENET: rutgers.edu!trotter!eecs1!dm2368 | | harvard.edu!trotter!eecs1!dm2368 | ____________________________________________________________________________
dave@tygra.Michigan.COM (David Conrad) (06/14/91)
In article <1991Jun12.071024.12162@nuchat.sccsi.com> robby@nuchat.sccsi.com (Robert Oliver Jr.) writes: > > > Hi, > > Has anyone out there been over 65520 in stack and had the program work? >I need to know how to get over the stack limit. Sence the pointer will not >work right. Is there something wrong with this statement ? > > Testing : Array[1..220] of ^Test; {Test is a Type Record} > >and calling the data with Testing[Index]^.Whois ??? > > Is there something wrong with this ? > I think there are two misunderstandings here. The first is that data is not stored in the stack, but the Data Segment (hence the name). I think the limit you are trying to break is the 64k limit on data. The second misunderstanding lies in the use of pointers; although you haven't given us a complete example program, I think I can guess the problem. If I've guessed wrong and am talking down at you, I apologize. When you declare a pointer, no space is allocated for the data. E.g. type Test = record name : string[50]; address : string[110]; end; var t : Test; tptr : ^Test; Variable t has 162 bytes allocated to it. (Remember, there's an additional byte for the length of the string.) There's room enough there for a name and an address. But variable tptr only has 4 bytes allocated to it. It can't contain a name and address, just a *pointer* to a Test record. You have to allocate the space from the heap, either with New and Dispose, or Getmem and Freemem. E.g. {continuing the previous example} begin t.name := 'Sam Pull'; t.address := '1234 Main Street, Nowhere IN 23456'; New (tptr); tptr^.name := 'Anne Teek'; tptr^.address := '101 Cherry Lane, Nowhere IN 23456'; writeln (t.name); writeln (tptr^.name); Dispose (tptr); {Now we'll use Getmem and Freemem} Getmem (tptr, sizeof(Test)); tptr^.name := 'Minnie Mum'; tptr^.address := '1 Little Place, Nowhere IN 23456'; writeln (tptr^.name); Freemem (tptr, sizeof(Test)); end. The output of this little program would, of course, be: Sam Pull Anne Teek Minnie Mum I hope I haven't insulted your intelligence, I realize this is much simpler faire than is usually seen in this newsgroup, but I decided to post instead of mail in case anyone else was having similar troubles. Pointers can be confusing, and it's easy to confuse the pointer with the thing pointed at, or vice versa. -- David R. Conrad dave@michigan.com -- = CAT-TALK Conferencing Network, Computer Conferencing and File Archive = - 1-313-343-0800, 300/1200/2400/9600 baud, 8/N/1. New users use 'new' - = as a login id. AVAILABLE VIA PC-PURSUIT!!! (City code "MIDET") = E-MAIL Address: dave@Michigan.COM