1) I seem to have encountered a memory leak.
I'm new to prolog,Gnu prolog, thus I'm hoping its my error and if so, i'd appreciate some guidance.
I'm using gnu prolog v 1.4.5
I'm building a cpp to prolog wrapper (using gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9) 5.4.0 ).
I'm trying to read a list of compounds. each compound is itself a compound
for example list = [ c1(Value1,c2(value2,c3(Value3,Value4),c3(Value5,Value6)),c2(Value7,c3(value8,Value9),c3(Value10,Value10))) ]
note that in some cases there are several occurrences of a compound/term ( C1 has two instances of c2. c2 has 2 instances of c3)).
i've managed to :
a. execute a Pl_Query_Call to get the data
b. parse and iterate the list data (using Pl_List_Length and Pl_Rd_Proper_List)
c. unify with c1 using Pl_Un_Compound_Check ( and access value1)
d. unify with c2 using Pl_Un_Compound_Check ( ana access values 2,7).
e. but when i add the code for unification with c3 , i encounter the following error "Fatal Error: Segmentation Violation (bad address: 0x852)"
more specifically
unification with c3 works i access values 3 & 4 successfully, but then i get the segfault when the second unification attempt with c2 is attempted ( so i can't access value7).
parsing c1 for all c2 compounds is done in a loop,
the same code works when unification with c3 is not present/attempted .
( i perform Pl_Mk_Variable for each itme of the 3 parameter of Pl_Un_Compound_Check - inside the loop,
and i fear this is causing the problem. )
2) i have a question regarding memory deallocation done by Pl_end_query.
lets say for example that i have :
func1 ()
{
PlTerm ArgArray[1];
ArgArray = Pl_Mk_Variable();
}
main
{
pl_begin_query(pl_True).
func1();
pl_end_query(PL_RECOVER).
}
how can pl_end_query(PL_RECOVER) free the memory if its address was stored on the stack and is no longer available?
Please advise,
Omer Brandis.