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* libpq-fe: PQgetvalue() ?
@ 2004-10-14 12:34 sad <sad@bankir.ru>
0 siblings, 2 replies; 4+ messages in thread
From: sad @ 2004-10-14 12:34 UTC (permalink / raw)
To: pgsql-sql
hi
does PQgetvalue() allocate memory rof its result, it returns ?
the answer will help me in problem:
should i free some cstring_variable if
{ cstring_variable=PQgetvalue(pgresult_variable,0,0); }
and could i PQclear(pgresult_varible) while cstring_varible is in use.
thnx
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: libpq-fe: PQgetvalue() ?
@ 2004-10-15 00:51 ljb <ljb220@mindspring.com>
parent: sad <sad@bankir.ru>
1 sibling, 0 replies; 4+ messages in thread
From: ljb @ 2004-10-15 00:51 UTC (permalink / raw)
To: pgsql-sql
sad@bankir.ru wrote:
> hi
>
> does PQgetvalue() allocate memory rof its result, it returns ?
> the answer will help me in problem:
> should i free some cstring_variable if
> { cstring_variable=PQgetvalue(pgresult_variable,0,0); }
> and could i PQclear(pgresult_varible) while cstring_varible is in use.
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: libpq-fe: PQgetvalue() ?
@ 2004-10-15 08:57 Christoph Haller <ch@rodos.fzk.de>
parent: sad <sad@bankir.ru>
1 sibling, 1 reply; 4+ messages in thread
From: Christoph Haller @ 2004-10-15 08:57 UTC (permalink / raw)
To: sad <sad@bankir.ru>; +Cc: pgsql-sql
AFAIK it does allocate memory.
You cannot PQclear(pgresult_varible) while cstring_varible is in use.
You do not need to free cstring_variable, PQclear(pgresult_varible) will do.
I personally prefer to allocate local memory, "strcpy" PQgetvalue,
and then PQclear. But that's a matter of taste, I suppose.
Regards, Christoph
sad wrote:
> hi
>
> does PQgetvalue() allocate memory rof its result, it returns ?
> the answer will help me in problem:
> should i free some cstring_variable if
> { cstring_variable=PQgetvalue(pgresult_variable,0,0); }
> and could i PQclear(pgresult_varible) while cstring_varible is in use.
>
> thnx
>
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: libpq-fe: PQgetvalue() ?
@ 2004-10-15 14:21 Tom Lane <tgl@sss.pgh.pa.us>
parent: Christoph Haller <ch@rodos.fzk.de>
0 siblings, 0 replies; 4+ messages in thread
From: Tom Lane @ 2004-10-15 14:21 UTC (permalink / raw)
To: Christoph Haller <ch@rodos.fzk.de>; +Cc: sad <sad@bankir.ru>; pgsql-sql
Christoph Haller <ch@rodos.fzk.de> writes:
> You cannot PQclear(pgresult_varible) while cstring_varible is in use.
> You do not need to free cstring_variable, PQclear(pgresult_varible) will do.
> I personally prefer to allocate local memory, "strcpy" PQgetvalue,
> and then PQclear. But that's a matter of taste, I suppose.
That is surely overkill.
PQgetvalue doesn't allocate new memory for its result. The docs are
reasonably clear, I thought:
The pointer returned by PQgetvalue points to storage that is part
of the PGresult structure. One should not modify the data it points
to, and one must explicitly copy the data into other storage if it
is to be used past the lifetime of the PGresult structure itself.
regards, tom lane
^ permalink raw reply [nested|flat] 4+ messages in thread
end of thread, other threads:[~2004-10-15 14:21 UTC | newest]
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-- links below jump to the message on this page --
2004-10-14 12:34 libpq-fe: PQgetvalue() ? sad <sad@bankir.ru>
2004-10-15 00:51 ` ljb <ljb220@mindspring.com>
2004-10-15 08:57 ` Christoph Haller <ch@rodos.fzk.de>
2004-10-15 14:21 ` Tom Lane <tgl@sss.pgh.pa.us>
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