I am having trouble with custom code that used to work but no longer
does in the latest beta sources. The trouble seems to be related to
symbol tables and/or reference counting etc. I managed to reduce the
issues to a small piece of code which crashes under some circumstances
but does not in the pre-805 J sources.
// in x.c
// Foreign 104 !: 1
...
case XC(104,1): R CDERIV(CIBEAM, jttest, 0, RMAX, 0, 0 );
...
static F1(jttest){A z, n, loc=jt->local;
RZ(w);
RZ(jt->local=stcreate(2,1L,0L,0L));
n=nfs(1,"A");
IS(n,w);
ex(box(cstr("A")));
symfreeh(jt->local,0L);
jt->local=loc;
R w;
}
The code does the following:
1. Create a local symbol table
2. Assign the argument w to A in the local symbol table
3. Erase A in the local symbol table
4. Erase the local symbol table
5. Return the argument
Doing the following in the J session causes a crash in symfreeh due to
accessing invalid memory in jt->sympv
104!:1 ] 1 2 3
1 2 3
B=. 1 2 3
104!:1 B
1 2 3
104!:1 B
1 2 3
104!:1 B
1 2 3
104!:1 B
1 2 3
104!:1 B
BOOM!
Is this a bug or is there a new way to deal with local symbol tables?
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