Re: calling by reference

[Bill Allombert <Bill.Allombert@math.u-bordeaux.fr>]

On Tue, Mar 11, 2025 at 04:00:13PM +0100, Ruud H.G. van Tol wrote:
> On 2025-03-11 15:46, Bill Allombert wrote:
> > On Tue, Mar 11, 2025 at 03:27:28PM +0100, Ruud H.G. van Tol wrote:
> > > The user manual states:
> > > 
> > > 2.7.2 [...] If an argument is prefixed by a tilde ~ in the function
> > > declaration and the call, it is passed by reference. (If either the
> > > declaration or the call is missing a tilde, we revert to a call by value.)
> > Actually it depends if the variable is lexically or dynamically scoped.
> > Please do not forget the ~!
> 
> But with a dynamically scoped L:
> 
> ? L=List([1,2,3]); print(L); listinsert(L,42,1); print(L); listpop(L,2);
> print(L);
> List([1, 2, 3])
> List([42, 1, 2, 3])
> List([42, 2, 3])
> 
> the missing ~ appears to work fine.

The reason is that listinsert and listpop are C functions, which are
prototyped.
But please really do not omit the ~, at some point PARI will require it.

Cheers,
Bill.