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* C text to string issue
@ 2004-08-16 10:22 Sam Stephens <tangent@inspire.net.nz>
2004-08-16 14:34 ` Re: C text to string issue Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 1 reply; 2+ messages in thread
From: Sam Stephens @ 2004-08-16 10:22 UTC (permalink / raw)
To: pgsql-interfaces
Hiya, I'm trying to write a function that takes a text argument as input, and converts it to a C
string to then use for file I/O.
However it crashes my postgres when it gets to the memcpy line (e.g. you get the Test A
notice and the Test B notice, but not the Test C notice)
The odd thing is my code is now based on genfile.c and I cannot see what I'm doing
differently/wrong.
http://cvs.pgadmin.org/cgi-bin/viewcvs.cgi/pgadmin-tools/support/genfile.c?rev=HEAD
I compile using the commands
gcc -c qpsolve.c -I/usr/src/postgresql-7.4.2/src/include
gcc -shared -o qpsolve.so qpsolve.o
cp qpsolve.so /usr/local/pgsql/lib -f
My command to create the function is
CREATE OR REPLACE FUNCTION F_QPSOLVE(text) RETURNS text
AS 'qpsolve.so'
LANGUAGE 'C' WITH (isStrict);
This is my source code, qpsolve.c
****
#include "postgres.h"
#include "fmgr.h"
/* Routine to write session variables */
PG_FUNCTION_INFO_V1(f_qpsolve);
text * f_qpsolve(text *arg)
{
char *filename;
int len=VARSIZE(arg)-VARHDRSZ;
elog(NOTICE, "test A");
filename = palloc(len+1);
elog(NOTICE, "test B");
memcpy(filename,VARDATA(arg), len);
elog(NOTICE, "test C");
filename[len]=0;
elog(NOTICE, filename);
return 0;
}
****
Your help solving this would be much appreciated.
All the best,
Sam
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: C text to string issue
2004-08-16 10:22 C text to string issue Sam Stephens <tangent@inspire.net.nz>
@ 2004-08-16 14:34 ` Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 0 replies; 2+ messages in thread
From: Tom Lane @ 2004-08-16 14:34 UTC (permalink / raw)
To: Sam Stephens <tangent@inspire.net.nz>; +Cc: pgsql-interfaces
"Sam Stephens" <tangent@inspire.net.nz> writes:
> PG_FUNCTION_INFO_V1(f_qpsolve);
> text * f_qpsolve(text *arg)
> {
This function is not written according to the V1 calling convention.
Either rewrite it or remove the INFO_V1 macro.
> return 0;
You most certainly do not want to return a null "text *" pointer.
regards, tom lane
^ permalink raw reply [nested|flat] 2+ messages in thread
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