[NTLUG:Discuss] Stack size or malloc problem

[Steve Baker]

Ralph Green, Jr wrote:
> Howdy,
>   I have been having a lot of problems with a program I am working on
> that uses the MySQL database.  It is a C program and itdoes many
> thousands of database updates.  I start having odd little problems that
> look to me like either 1)insufficient stack space,

...are you maybe using Fedora?  They (for some unaccountable reason)
reduced the default stack size in the kernel.

> or 2) malloc and free
> problems.  I know my mallocs and free are right...

Are you **SURE** ?  That's by far the most likely thing.  Something,
somewhere in your program could easily be scribbling somewhere it
shouldn't.  A program with that sort of error can sometimes appear to
be working for *years* before the problem finally surfaces.

>  I say the code is good because I have cut it out, put it in a
> small test program and it passed.

That proves *NOTHING*.

> I can tell where it dies using gdb,
> but I am stumped.

Try:

  export MALLOC_CHECK_ = 2

...then run your program normally (without gdb)

Do a 'man malloc' to find an explanation of what this does.

---------------------------- Steve Baker -------------------------
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