Thread: how to call the function--pqCatenateResultError()
Hello!~
Now i encounter a function call problem in PostgreSQL's psql module!
The situation is as follow:
In ./src/bin/psql/common.c, I want to call the function pqCatenateResultError().
Function pqCatenateResultError() is declared in ./src/interfaces/libpq/libpq-init.h
extern void pqCatenateResultError(PGresult *res, const char *msg);
and is defined in ./src/interfaces/libpq/fe-exec.c
void
pqCatenateResultError(PGresult *res, const char *msg)
{
PQExpBufferData errorBuf;
if (!res || !msg)
return;
initPQExpBuffer(&errorBuf);
if (res->errMsg)
appendPQExpBufferStr(&errorBuf, res->errMsg);
appendPQExpBufferStr(&errorBuf, msg);
pqSetResultError(res, errorBuf.data);
termPQExpBuffer(&errorBuf);
}
To call this function in ./common.c, I include 'libpq-init.h' in ./src/bin/psql/common.h .
As ./common.c include the header file 'common.h'.
But when I use pqCatenateResultError() in ./common.c, It appears "undefined reference to pqCatenateResultError()" first.
So I include 'extern void pqCatenateResultError(PGresult *res, const char *msg);' at the begining of './common.c' .
But this change make no difference to the result.
I do not know why this happened! Someone hlep me! Thank you.
There is another situation similar to the situation above:
Function PQexec() is declared in ./src/interfaces/libpq/libpq-fe.h and defined in ./src/interfaces/libpq/fe-exec.c
extern PGresult *PQexec(PGconn *conn, const char *query);
I can call this function with no error happening!
These two situation puzzled me!~
From: Stone
2011/6/27 _石头 <tanjia76@qq.com>:
> Hello!~
>
> Now i encounter a function call problem in PostgreSQL's psql module!
>
> The situation is as follow:
> In ./src/bin/psql/common.c, I want to call the
> function pqCatenateResultError().
> Function pqCatenateResultError() is declared in
> ./src/interfaces/libpq/libpq-init.h
> extern void
> pqCatenateResultError(PGresult *res, const char *msg);
> and is defined in ./src/interfaces/libpq/fe-exec.c
> void
> pqCatenateResultError(PGresult *res, const
> char *msg)
> {
> PQExpBufferData errorBuf;
> if (!res || !msg)
> return;
> initPQExpBuffer(&errorBuf);
> if (res->errMsg)
> appendPQExpBufferStr(&errorBuf, res->errMsg);
> appendPQExpBufferStr(&errorBuf, msg);
> pqSetResultError(res, errorBuf.data);
> termPQExpBuffer(&errorBuf);
> }
> To call this function in ./common.c, I include 'libpq-init.h' in
> ./src/bin/psql/common.h .
> As ./common.c include the header file 'common.h'.
> But when I use pqCatenateResultError() in ./common.c, It appears
> "undefined reference to pqCatenateResultError()" first.
>
> So I include 'extern void pqCatenateResultError(PGresult *res, const
> char *msg);' at the begining of './common.c' .
> But this change make no difference to the result.
>
> I do not know why this happened! Someone hlep me! Thank you.
> There is another situation similar to the situation above:
> Function PQexec() is declared in ./src/interfaces/libpq/libpq-fe.h and
> defined in ./src/interfaces/libpq/fe-exec.c
> extern PGresult *PQexec(PGconn *conn, const
> char *query);
> I can call this function with no error happening!
> These two situation puzzled me!~
Are you developing on Windows, by any chance?
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company