From: James Williamson <james@nameonthe.net>
To: pgsql-interfaces@postgresql.org
Subject: Re: Segmentation Fault
Date: Thu, 3 Apr 2003 12:26:54 +0100
Message-ID: <000401c2f9d3$ee3c9a80$6600a8c0@JAMES> (raw)
References: <3E8C19B5.6050106@rodos.fzk.de>
----- Original Message -----
From: "Christoph Haller" <ch@rodos.fzk.de>
> >
> > Oh, I'm so sorry....
> > I've made a stupid mistake... and this mistake is at the cost of 3 days
> > work.
> > The segmentation fault is totally irrelevant to the time functions in
> > previous thread.
> >
> Keep your head.
> AFAICT segmentation faults are every C programmer's nightmare
> and best known for hard to find. I know of people searching for
> mistakes even longer and I've seen mistakes more stupid than yours.
>
> >
> > Here I have one more question, is there any debugging tools other
> than GDB?
> > I'm not quite used to it, debugging segmentation fault is really a
> pain. :-(
> >
Have you looked at efence, purify and valgrind?
Regards,
James Williamson
www.nameonthe.net
Tel: +44 208 7415453
Fax: + 44 208 7411615
> I don't know of one. I'm using xdb on HP-UX, which is quite similar I
> suppose.
> I've found it useful when trying to track down, do not trace, but let it
> simply run
> within the debugger and then use the "down" command to find your code
area.
> There is also a function called memorymap(int show_stats) which often
> detects
> memory faults before the operating systems does.
>
> > len =strlen(PQgetvalue(res, 0, i)) * 2 + 1; // <=========
> Why not using PQgetlength(res, 0, i)?
> > PQescapeString(tmp2, PQgetvalue(res, 0, i), len); // <=========
> One last question:
> Why are you using PQescapeString on PQgetvalue?
>
> The doc says:
> If you want to include strings that have been received from a source
> that is not trustworthy (for example, because a random user entered
> them), you cannot directly include them in SQL queries for security
> reasons. Instead, you have to quote special characters that are
> otherwise interpreted by the SQL parser.
>
> So PQgetvalue is trustworthy. There should be no need to call
> PQescapeString,
> except you were using a binary cursor. But if you were using one, then why
> would you want to escape the result instead of just using a normal cursor?
>
> Regards, Christoph
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
>
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To: pgsql-interfaces@postgresql.org
Cc: james@nameonthe.net
Subject: Re: Segmentation Fault
In-Reply-To: <000401c2f9d3$ee3c9a80$6600a8c0@JAMES>
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