Stack checking, core dumps, and embedding R

Simon Urbanek wrote:

On Apr 11, 2006, at 5:34 AM, A.J. Rossini wrote:

I've been experiencing some interesting stack warnings recently
when moving from R 2.2.x to the R 2.3.0 series and the R 2.4.0
series.  In particular, I'm getting warnings of "Error: C stack
usage is too close to the limit" before segfaulting, and this
wasn't happening under the 2.2.x series.

Here's the question statement:  (ONLY) In the situation where one
is embedding R, is anyone else seeing this occur with recent (past
2 weeks) versions of R (both the 2.3.x and 2.4.x series)?

When embedding R, the stack base is set to -1 (which is almost
certainly wrong) if R cannot find the stack base using some system
method. I have just fixed the detection for OS X, so you shouldn't

My question may be unrelated, but I stumbled across it while trying to
understand the above problem. The following is from R-trunk r37731
src/unix/system.c in Rf_initialize_R() and is run when the os is neither
linux nor freebsd:

    if(R_running_as_main_program) {
    /* This is not the main program, but unless embedded it is
       near the top, 5540 bytes away when checked. */
    R_CStackStart = (uintptr_t) &i + 6000;
    }

This is run before we know which direction the stack grows:

    {
        int ii;
    /* 1 is downwards */
        R_CStackDir = ((uintptr_t)&i > (uintptr_t)&ii) ? 1 : -1;
    }

So, R_CStackStart is being set to the address of i (on the stack) plus
6000 bytes, an approximation to somewhere near the beginning of the
stack, but this presumes the stack grows down, right? What if it grows
up? Then shouldn't we subtract 6000 bytes?