Hi,

I am trying to allocate only the needed amount of memory when working with static tables in cobol. The table(which is part of a data-area) is then used as a parameter in json generate statement.

Suppose there are two programs. Program TestA and TestB. TestA calls TestB which is the one responsible to allocate n amount of memory depending on the size of the table. This means that even though the table has a boundary of 50000 items I want that the amount of byte allocated to the data-area should be less than that(depending on the amount of items populated which is known only in runtime).
Below is the an example:

program-id. TestA as "TestA"
environment division.

configuration section.

data division.
working-storage section.

01 foo-pointer.
04 tmp-ptr pointer.
1 tbl-size pic 9(8) value 0.
1 outputarea pic x(53400356) value space.

linkage section.
1 fooArea.
2 fooResponse.
3 fooRespOkPayload.
4 fooRespOkCode pic x(10) value space.
4 fooRespOkMessage pic x(100) value space.
4 fooRespObject.
5 fooRespObjectName pic x(50).
5 fooRespList occurs 50000 depending on tbl-size.
6 fooRespObjectOwnership pic x(40) value
space.
3 fooRespFailPayload.
4 fooRespFailCode pic 9(6) value 0.
4 fooRespFailMessage pic x(100) value space.
$set sourceformat "fixed"

procedure division.

call "TestB" using fooArea foo-pointer tbl-size

set address of fooArea to tmp-ptr
if tmp-ptr = null
display "Null"
stop run
end-if

json generate outputarea from fooArea
on exception
display
"Error generating json using dynamic allocation"
end-json
display outputarea
free tmp-ptr
cancel "TestB"
goback

end program TestA.

copy "cblproto".
program-id. TestB as "TestB".

environment division.
configuration section.

data division.
working-storage section.
1 x pic 9(8).
1 totalLengthOfFoo pic 9(15) value 0.
1 lgnthOfSingleItem pic 9(15) value 0.
1 maxOccrTbl pic 9(8) value 0.
1 sizeOfOnlyTbl pic 9(8) value 0.
1 sizeOfSingleElem pic 9(8) value 0.
1 byteToAllocate pic 9(15) value 0.
1 remainderSizeOfInput pic 9(8) value 0.
1 realSizeOfSingleElem pic 9(8) value 0.
linkage section.
1 fooArea.
2 fooResponse.
3 fooRespOkPayload.
4 fooRespOkCode pic x(10) value space.
4 fooRespOkMessage pic x(100) value space.
4 fooRespObject.
5 fooRespObjectName pic x(50).
5 fooRespList occurs 50000 depending on tbl-size.
6 fooRespObjectOwnership pic x(40) value
space.
3 fooRespFailPayload.
4 fooRespFailCode pic 9(6) value 0.
4 fooRespFailMessage pic x(100) value space.
01 foo-pointer.
04 tmp-ptr pointer.
1 tbl-size pic 9(8) value 0.

procedure division using fooArea foo-pointer tbl-size.

display "TestB"
move 50000 to x tbl-size
move length of fooArea to totalLengthOfFoo
move length of fooRespList to lgnthOfSingleItem*> 40
display length of fooRespObject
display length of fooRespObjectName
compute maxOccrTbl = (length of fooRespObject -
function length(fooRespObjectName)) /
lgnthOfSingleItem
compute sizeOfSingleElem = totalLengthOfFoo / maxOccrTbl
compute sizeOfOnlyTbl = lgnthOfSingleItem * maxOccrTbl
compute remainderSizeOfInput =
totalLengthOfFoo - sizeOfOnlyTbl
move 2 to x

compute byteToAllocate = (sizeOfSingleElem * x +
remainderSizeOfInput)
allocate byteToAllocate characters
returning tmp-ptr

if tmp-ptr = null
display "Could not allocate mem"
end-if

set address of fooArea to tmp-ptr
initialize fooArea(1:byteToAllocate)

move "Workshop" to fooRespObjectName
move "Test1" to fooRespObjectOwnership(1)
move "Test2" to fooRespObjectOwnership(2)
move x to tbl-size
goback
end program TestB.

The result of the json generate can be seen below

I do believe that not enough data is allocated because when I try to assign a value to fooRespFailMessage after setting address of fooArea to tmp-ptr I get the 114 error code(Attempt to access item beyond bounds of memory).

Any help is appreciated.