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* Exception Handling in C-Language Functions?
@ 2012-12-03 05:18 rahul143 <[email protected]>
0 siblings, 2 replies; 4+ messages in thread
From: rahul143 @ 2012-12-03 05:18 UTC (permalink / raw)
To: [email protected]
I have the created a C-Language function (code is below). Now, I
wonder: How do I handle exceptions, for example if malloc cannot assign
the necessary memory? Do "palloc" and "pfree" handle such a case
cleanly? Should I simply use an "assert"?
#include "postgres.h"
#include <string.h>
#include <stdlib.h>
#include "fmgr.h"
#include "libinn.h"
PG_FUNCTION_INFO_V1(ffiinews_uwildmat);
/* Wrapper for INN's function uwildmat. Needs parameters in UTF-8. */
Datum ffiinews_uwildmat(PG_FUNCTION_ARGS) {
VarChar *text = PG_GETARG_VARCHAR_P(0);
VarChar *pattern = PG_GETARG_VARCHAR_P(1);
int text_len = VARSIZE(text)-VARHDRSZ;
int pattern_len = VARSIZE(pattern)-VARHDRSZ;
char *tmp_text = (char *)malloc(text_len+1);
if (tmp_text == NULL)
; /* What now? */
char *tmp_pattern = (char *)malloc(pattern_len+1);
if (tmp_pattern == NULL)
; /* What now? */
strncpy(tmp_text, VARDATA(text), text_len);
tmp_text[text_len] = '\0';
strncpy(tmp_pattern, VARDATA(pattern), pattern_len);
tmp_pattern[pattern_len] = '\0';
bool matches = uwildmat(tmp_text, tmp_pattern);
-----
--
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^ permalink raw reply [nested|flat] 4+ messages in thread
* MODERATOR WARNING Re: [GENERAL] Exception Handling in C-Language Functions?
@ 2012-12-03 06:14 Alvaro Herrera <[email protected]>
parent: rahul143 <[email protected]>
1 sibling, 1 reply; 4+ messages in thread
From: Alvaro Herrera @ 2012-12-03 06:14 UTC (permalink / raw)
To: [email protected]; [email protected]; +Cc: [email protected]; pgsql-www
MODERATOR WARNING
I noticed that this guy Rahul seems to be reinjecting old list emails
somehow. Please don't approve anything coming from him. Observe this
example:
http://postgresql.1045698.n5.nabble.com/Re-GENERAL-MS-Access-and-Stored-procedures-td1843848.html
http://postgresql.1045698.n5.nabble.com/Re-GENERAL-MS-Access-and-Stored-procedures-td5734652.html
The original message was posted in 2005!
The message here is this one (also in 2005):
http://postgresql.1045698.n5.nabble.com/GENERAL-Exception-Handling-in-C-Language-Functions-td1843896...
I have no idea what's going on. Maybe it's something to do with Nabble.
There are others pending moderation in pgsql-admin and pgsql-hackers too.
rahul143 wrote:
> I have the created a C-Language function (code is below). Now, I
> wonder: How do I handle exceptions, for example if malloc cannot assign
> the necessary memory? Do "palloc" and "pfree" handle such a case
> cleanly? Should I simply use an "assert"?
>
> #include "postgres.h"
> #include <string.h>
> #include <stdlib.h>
> #include "fmgr.h"
> #include "libinn.h"
>
> PG_FUNCTION_INFO_V1(ffiinews_uwildmat);
>
> /* Wrapper for INN's function uwildmat. Needs parameters in UTF-8. */
> Datum ffiinews_uwildmat(PG_FUNCTION_ARGS) {
> VarChar *text = PG_GETARG_VARCHAR_P(0);
> VarChar *pattern = PG_GETARG_VARCHAR_P(1);
> int text_len = VARSIZE(text)-VARHDRSZ;
> int pattern_len = VARSIZE(pattern)-VARHDRSZ;
> char *tmp_text = (char *)malloc(text_len+1);
> if (tmp_text == NULL)
> ; /* What now? */
> char *tmp_pattern = (char *)malloc(pattern_len+1);
> if (tmp_pattern == NULL)
> ; /* What now? */
> strncpy(tmp_text, VARDATA(text), text_len);
> tmp_text[text_len] = '\0';
> strncpy(tmp_pattern, VARDATA(pattern), pattern_len);
> tmp_pattern[pattern_len] = '\0';
> bool matches = uwildmat(tmp_text, tmp_pattern);
>
>
>
> -----
>
>
>
>
> --
> View this message in context: http://postgresql.1045698.n5.nabble.com/GENERAL-Exception-Handling-in-C-Language-Functions-tp5734656...
> Sent from the PostgreSQL - general mailing list archive at Nabble.com.
>
>
> --
> Sent via pgsql-general mailing list ([email protected])
> To make changes to your subscription:
> http://www.postgresql.org/mailpref/pgsql-general
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: MODERATOR WARNING Re: [GENERAL] Exception Handling in C-Language Functions?
@ 2012-12-03 13:38 David Fetter <[email protected]>
parent: Alvaro Herrera <[email protected]>
0 siblings, 0 replies; 4+ messages in thread
From: David Fetter @ 2012-12-03 13:38 UTC (permalink / raw)
To: Alvaro Herrera <[email protected]>; +Cc: [email protected]; [email protected]; pgsql-www
OK :)
Is there a way to do this automatically?
Cheers,
David.
On Mon, Dec 03, 2012 at 03:14:54AM -0300, Alvaro Herrera wrote:
> MODERATOR WARNING
>
> I noticed that this guy Rahul seems to be reinjecting old list emails
> somehow. Please don't approve anything coming from him. Observe this
> example:
>
> http://postgresql.1045698.n5.nabble.com/Re-GENERAL-MS-Access-and-Stored-procedures-td1843848.html
> http://postgresql.1045698.n5.nabble.com/Re-GENERAL-MS-Access-and-Stored-procedures-td5734652.html
> The original message was posted in 2005!
>
> The message here is this one (also in 2005):
> http://postgresql.1045698.n5.nabble.com/GENERAL-Exception-Handling-in-C-Language-Functions-td1843896...
>
> I have no idea what's going on. Maybe it's something to do with Nabble.
> There are others pending moderation in pgsql-admin and pgsql-hackers too.
>
> rahul143 wrote:
> > I have the created a C-Language function (code is below). Now, I
> > wonder: How do I handle exceptions, for example if malloc cannot assign
> > the necessary memory? Do "palloc" and "pfree" handle such a case
> > cleanly? Should I simply use an "assert"?
> >
> > #include "postgres.h"
> > #include <string.h>
> > #include <stdlib.h>
> > #include "fmgr.h"
> > #include "libinn.h"
> >
> > PG_FUNCTION_INFO_V1(ffiinews_uwildmat);
> >
> > /* Wrapper for INN's function uwildmat. Needs parameters in UTF-8. */
> > Datum ffiinews_uwildmat(PG_FUNCTION_ARGS) {
> > VarChar *text = PG_GETARG_VARCHAR_P(0);
> > VarChar *pattern = PG_GETARG_VARCHAR_P(1);
> > int text_len = VARSIZE(text)-VARHDRSZ;
> > int pattern_len = VARSIZE(pattern)-VARHDRSZ;
> > char *tmp_text = (char *)malloc(text_len+1);
> > if (tmp_text == NULL)
> > ; /* What now? */
> > char *tmp_pattern = (char *)malloc(pattern_len+1);
> > if (tmp_pattern == NULL)
> > ; /* What now? */
> > strncpy(tmp_text, VARDATA(text), text_len);
> > tmp_text[text_len] = '\0';
> > strncpy(tmp_pattern, VARDATA(pattern), pattern_len);
> > tmp_pattern[pattern_len] = '\0';
> > bool matches = uwildmat(tmp_text, tmp_pattern);
> >
> >
> >
> > -----
> >
> >
> >
> >
> > --
> > View this message in context: http://postgresql.1045698.n5.nabble.com/GENERAL-Exception-Handling-in-C-Language-Functions-tp5734656...
> > Sent from the PostgreSQL - general mailing list archive at Nabble.com.
> >
> >
> > --
> > Sent via pgsql-general mailing list ([email protected])
> > To make changes to your subscription:
> > http://www.postgresql.org/mailpref/pgsql-general
>
>
> --
> Álvaro Herrera http://www.2ndQuadrant.com/
> PostgreSQL Development, 24x7 Support, Training & Services
--
David Fetter <[email protected]> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: [email protected]
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^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Exception Handling in C-Language Functions?
@ 2012-12-03 14:42 Merlin Moncure <[email protected]>
parent: rahul143 <[email protected]>
1 sibling, 0 replies; 4+ messages in thread
From: Merlin Moncure @ 2012-12-03 14:42 UTC (permalink / raw)
To: rahul143 <[email protected]>; +Cc: [email protected]
On Sun, Dec 2, 2012 at 11:18 PM, rahul143 <[email protected]> wrote:
> I have the created a C-Language function (code is below). Now, I
> wonder: How do I handle exceptions, for example if malloc cannot assign
> the necessary memory? Do "palloc" and "pfree" handle such a case
> cleanly? Should I simply use an "assert"?
>
> #include "postgres.h"
> #include <string.h>
> #include <stdlib.h>
> #include "fmgr.h"
> #include "libinn.h"
>
> PG_FUNCTION_INFO_V1(ffiinews_uwildmat);
>
> /* Wrapper for INN's function uwildmat. Needs parameters in UTF-8. */
> Datum ffiinews_uwildmat(PG_FUNCTION_ARGS) {
> VarChar *text = PG_GETARG_VARCHAR_P(0);
> VarChar *pattern = PG_GETARG_VARCHAR_P(1);
> int text_len = VARSIZE(text)-VARHDRSZ;
> int pattern_len = VARSIZE(pattern)-VARHDRSZ;
> char *tmp_text = (char *)malloc(text_len+1);
> if (tmp_text == NULL)
> ; /* What now? */
> char *tmp_pattern = (char *)malloc(pattern_len+1);
> if (tmp_pattern == NULL)
> ; /* What now? */
> strncpy(tmp_text, VARDATA(text), text_len);
> tmp_text[text_len] = '\0';
> strncpy(tmp_pattern, VARDATA(pattern), pattern_len);
> tmp_pattern[pattern_len] = '\0';
> bool matches = uwildmat(tmp_text, tmp_pattern);
yes, you should always use database memory api: palloc/pfree and if
necessary memory context switching. memory allocation error then
raises database exception. any situation that raises an exception or
other critical needs to be caught and rethrown as database exception
(ereport, etc).
merlin
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^ permalink raw reply [nested|flat] 4+ messages in thread
end of thread, other threads:[~2012-12-03 14:42 UTC | newest]
Thread overview: 4+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2012-12-03 05:18 Exception Handling in C-Language Functions? rahul143 <[email protected]>
2012-12-03 06:14 ` MODERATOR WARNING Re: [GENERAL] Exception Handling in C-Language Functions? Alvaro Herrera <[email protected]>
2012-12-03 13:38 ` Re: MODERATOR WARNING Re: [GENERAL] Exception Handling in C-Language Functions? David Fetter <[email protected]>
2012-12-03 14:42 ` Merlin Moncure <[email protected]>
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