Re: error handlling in recursive function

On May 30, 10:17 am, David Resnick <lndresn...@xxxxxxxxx> wrote:
On May 30, 11:46 am, j...@xxxxxxxxxxx (Jens Thoms Toerring) wrote:





David Resnick <lndresn...@xxxxxxxxx> wrote:
On May 30, 9:22 am, pereges <Brol...@xxxxxxxxx> wrote:
How to to go about this ? Suppose a malloc inside a recursive function
has failed and you want to set the error flag and return it to the
calling function(the one which called the recursive function in the
first place)
Options seem to be:
1) Propagate the flag back through the stack of recursive functions,
checking for it at each invocation.  This is the best way if you need
to, say, release resources in each invocation of the recursive
function, which seems possible given that you are mallocing in the
recursion.
2) Use setjmp (before entering recursion) and longjmp to hop back on
error.

A third option might be to have a global variable (at file scope)
that gets set if an error occurs. Ok, global variables are EVIL,
but this may be one of the cases where their use can simplify
things a bit...

Sure, and a fourth is to pass down a pointer to a variable to use for
error reporting.  I gave the answer I did because I interpreted his
question as being also how to reasonably unwind the stack of recursive
invocations when hitting an error condition...

Yet another one is to use signal()/raise(). E.g.:
http://publications.gbdirect.co.uk/c_book/chapter9/signal_handling.html
.

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