On 23/12/15 09:37, Santiago Amposta wrote: > Hello: > I use fpc 2.6.4 and I have a problem of memory leaks, strange errors, > etc. Finally I have tracked it to this: > > TSimpleArrayString=object > List:array of String; > end; > > TDerivedArrayString=object(TSimpleArrayString) > other_field:integer; > end; > > procedure TestSimple; > var > A:TSimpleArrayString; > begin > setLength(A.List,0); > end; > > procedure TestDerived; > var > A:TDerivedArrayString; > begin > setLength(A.List,0); > end; > > > TestSimple; // Works Fine, > TestDerived; // rises an exception SIGSEGV on setLength > > What am I doing wrong? > I might be wrong... but I just tried:
stepping into TestSimple in the order OP specified, hovering over A.List (actually over .List only, see below*) gives A.List = (0x0) before setLength and A.List = () after the setLength; then stepped through to TestDerived, in which the hover over .List gives A.List = () before setLength, and an External: SIGSEGV At Address 403CDC when trying to step over setLength Then if I change the order TestDerived; // first TestSimple; // second and step through, the A.List in Test Derived is A.List = () from the start, it is as-if it was preinitialized? But then. If I comment out the other_field, both routines pass through with A.List = (0x0) in TestSimple before SetLength, it also seems to pass without a problem and without the * problem below, even with A.List = () before and after SetLength. * problem : with the other_field still IN TDerivedArrayString, if I step through the (passing with no error) TestSimple, and hover mouse over A, I get a GDB crash. Regardless which A I hover over (the one in Test Derived does that too, even if out of scope [execution point currently in the other Test procedure] Again this does NOT happen with the other_field commented out. If I run either one Test* procedures at a time between rebuilds, with other_field defined, TestSimple passes with no error, TestDerived shows .List hovering A.List = (0x10000 '=') ; hovering over A crashes GDB too; Say if I only leave TestDerived call, and if I pause execution before SetLength, hovering over .List in EITHER procedure shows A.List = () (yes even in TestSimple which is commented out in main begin..end;) (and I get GDB crash when hovering over A of either procedure) BUT. If I truly comment out the unused procedure, only leaving the one currently being tested, like TestDerived, hovering over .List before SetLength call gives A.List = (0x10000 '=') hovering over A crashes GDB after rebuild, program completes with NO SIGSEGV. ? FPC 2.6.4 under Lazarus 1.4.4 from tarball release [ 2015-10-03, svn 49931 i386-win32-win32/win64 ] under WinXP SP3. _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
