There is one other possibility:
It may be that the calloc/free pair picked up by the tcltk package DLL
is different from the pair picked up when building base R. (We provide
our own malloc framework, but if the macros aren't quite right it may
be that the system malloc is picked up in some cases). In that case
using Calloc and free would be mismatching the malloc systems and
probably segfault.
If that is indeed happening we should fix it, but using Free with
Calloc should cure the immediate symptom.
Best,
luke
On Sun, 7 Jun 2020, luke-tier...@uiowa.edu wrote:
On Sun, 7 Jun 2020, peter dalgaard wrote:
So this wasn't tested for a month?
Anyways, Free() is just free() with a check that we're not freeing a null
pointer, followed by setting the pointer to NULL. At that point of tcltk.c,
we have
for (objc = i = 0; i < length(avec); i++){
const char *s;
char *tmp;
if (!isNull(nm) && strlen(s = translateChar(STRING_ELT(nm, i)))){
// tmp = calloc(strlen(s)+2, sizeof(char));
tmp = Calloc(strlen(s)+2, char);
*tmp = '-';
strcpy(tmp+1, s);
objv[objc++] = Tcl_NewStringObj(tmp, -1);
free(tmp);
}
if (!isNull(t = VECTOR_ELT(avec, i)))
objv[objc++] = (Tcl_Obj *) R_ExternalPtrAddr(t);
}
and I can't see how tmp can be NULL at the free(), nor can I see it
mattering if it is not set to NULL (notice that it goes out of scope with
the for loop).
Right. And the calloc->Calloc change doesn't look like an issue either
-- just checking for a NULL.
If the crash is happening in free() then that most likely means
corrupted malloc data structures. Unfortunately that could be
happening anywhere.
Best bet to narrow this down is for someone with a good Windows setup
who can reproduce this to bisect the svn commits and see at what
commit this started happening. Unfortunately my office Windows machine
isn't responding and it will probably take some time to get that
fixed.
Best,
luke
-pd
On 7 Jun 2020, at 16:00 , Jeroen Ooms <jeroeno...@gmail.com> wrote:
On Sun, Jun 7, 2020 at 3:13 AM Fox, John <j...@mcmaster.ca> wrote:
Hi,
The following code, from the examples in ?TkWidgets , immediately crashes
R 4.0.1 for Windows:
--------------------- snip --------------------
library("tcltk")
tt <- tktoplevel()
label.widget <- tklabel(tt, text = "Hello, World!")
button.widget <- tkbutton(tt, text = "Push",
command = function()cat("OW!\n"))
tkpack(label.widget, button.widget) # geometry manager
--------------------- snip --------------------
I can reproduce this. The backtrace shows the crash happens in
dotTclObjv [/src/library/tcltk/src/tcltk.c@243 ]. This looks like a
bug that was introduced by commit 78408/78409 about a month ago. I
think the problem is that this commit changes 'calloc' to 'Calloc'
without changing the corresponding 'free' to 'Free'.
This has nothing to do with the Windows build or installation. Nothing
has changed in the windows build procedure between 4.0.0 and 4.0.1.
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--
Luke Tierney
Ralph E. Wareham Professor of Mathematical Sciences
University of Iowa Phone: 319-335-3386
Department of Statistics and Fax: 319-335-3017
Actuarial Science
241 Schaeffer Hall email: luke-tier...@uiowa.edu
Iowa City, IA 52242 WWW: http://www.stat.uiowa.edu
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