Re: a recursion bug

[Greg Wooledge]

On Wed, Oct 03, 2012 at 05:07:16AM +0000, Yuxiang Cao wrote:
> Hi,
> After second thought, I carefully read the bash manual page and find this
> information. Functions may be recursive. The FUNCNEST variable may be used to
> limit the depth of the function call stack and restrict the number of
> function invocations. By default, no limit is placed on the number of
> recursive calls. So in my example, what I think I can do is to limit the
> times of recursive calls. So I simply export FUNCNEST variable as " export
> FUNCNEST=500", however, it doesn't work. That could be a bug for bash, right?

It would help if you show what you're doing and what the result is.
It seems to work correctly here:

imadev:~$ bash-4.2.28 -c 'FUNCNEST=100; a() { echo "$1"; a $(($1+1)); }; a 1' 
2>&1 | tail
92
93
94
95
96
97
98
99
100
bash-4.2.28: a: maximum function nesting level exceeded (100)

Without the FUNCNEST, it runs for several seconds, and then:

imadev:~$ bash-4.2.28 -c 'a() { echo "$1"; a $(($1+1)); }; a 1' 2>&1 | tail     
Pid 4466 received a SIGSEGV for stack growth failure.
Possible causes: insufficient memory or swap space,
or stack size exceeded maxssiz.
6534
6535
6536
6537
6538
6539
6540
6541
6542
6543
imadev:~$ ls -l core
-rw-------   1 wooledg    pgmr       19908052 Oct  3 08:38 core
imadev:~$ file core
core:           core file from 'bash-4.2.28' - received SIGSEGV

(Happy, Linda?)