Problem:
How can I pass a null terminates string to .Net so that the null is retained in the string being passed?
The calling program is Unmanaged COBOL and it will be using COM Interop to call the .Net assembly.
Resolution:
You need to use a chararray to pass this data across as you can specify the size of the chararray when you create it.
Some example code that does this is:-
*> This is required for OLE applications
$set ooctrl( P)
program-id. testnet.
special-names.
call-convention 66 is winapi. *> Non Litlinked apis
class-control.
*> OLE automation classes
olesup is class "olesup"
dotnet is class "$OLE$TestCOBOLNull.CTester"
oleVariant is class "olevar"
CharacterArray is class "chararry"
.
working-storage section.
copy mfole.
01 string1 pic x(8) value "12345678".
01 string2 pic x(8) value spaces.
01 string3 pic x(200) value spaces.
01 obj-string3 object reference.
01 inta pic s9(9) comp-5 value 1.
01 intb pic s9(9) comp-5 value 2.
01 ws-dnobj object reference.
01 ws-missingref object reference.
01 mynull object reference.
01 ws-ptr pointer.
01 retval pic s9(9) comp-5.
01 ws-size PIC S9(9) COMP-5.
linkage section.
01 lnk-var VARIANT.
procedure division.
start-it section.
invoke dotnet "new" returning ws-dnobj
invoke ws-dnobj "TestMethod"
using by reference string1
by reference string2
by value inta
by value intb
returning retval
invoke oleVariant "new" returning mynull
invoke mynull "getVariantAddress" returning ws-ptr
set address of lnk-var to ws-ptr
move DISP-E-PARAMNOTFOUND
to VARIANT-VT-SCODE of lnk-var
invoke ws-dnobj "TestMethod"
using by reference string1
by reference mynull
by value inta
by value intb
returning retval
invoke ws-dnobj "TestMethod"
using by reference string1
by reference mynull
by value inta
by value intb
returning retval
***** Setup a chararray to pass data
move z"1234" to string3
perform create-null-terminated-bstr
invoke ws-dnobj "TestMethod"
using by reference string1
by reference obj-string3
by value inta
by value intb
returning retval
***** Setup a chararray to pass data
move z"1234567890123456789012345678901234567890" to string3
perform create-null-terminated-bstr
invoke ws-dnobj "TestMethod"
using by reference string1
by reference obj-string3
by value inta
by value intb
returning retval
display "Press return to TERMINATE".
accept retval
stop run
.
create-null-terminated-bstr section.
move length of string3 to ws-size
perform varying ws-size from length of string3 by -1
until ((string3(ws-size:1) = x"00") or (ws-size = 1))
continue
end-perform
invoke CharacterArray "withlengthvalue" using ws-size
string3
returning obj-string3
.
