Re: error when create dll for postgres

On 3/30/09, eehab hamzeh <[email protected]> wrote:
>
> hello, thanks for your help.
> i was being able to create the lib for the first function as below. the
> compiler work when the variable are int, if i declare any other variable
> like below, i start to recive erros. please see below the code and the
> recieved errors
>
> #include "postgres.h"
> #include <string.h>
> #include "fmgr.h"
>
> #ifdef PG_MODULE_MAGIC
> PG_MODULE_MAGIC;
> #endif
>
> /* by value */
>
> PG_FUNCTION_INFO_V1(add_one);
>
> Datum
> add_one(PG_FUNCTION_ARGS)
> {
>     int32   arg = PG_GETARG_INT32(0);
>
>     PG_RETURN_INT32(arg + 1);
> }
>
> /* by reference, fixed length */
>
> PG_FUNCTION_INFO_V1(add_one_float8);
>
> Datum
> add_one_float8(PG_FUNCTION_ARGS)
> {
>     /* The macros for FLOAT8 hide its pass-by-reference nature. */
>     float8   arg = PG_GETARG_FLOAT8(0);
>
>     PG_RETURN_FLOAT8(arg + 1.0);
> }
>
> PG_FUNCTION_INFO_V1(makepoint);
>
> Datum
> makepoint(PG_FUNCTION_ARGS)
> {
>     /* Here, the pass-by-reference nature of Point is not hidden. */
>     Point     *pointx = PG_GETARG_POINT_P(0);
>     Point     *pointy = PG_GETARG_POINT_P(1);
>     Point     *new_point = (Point *) palloc(sizeof(Point));
>
>     new_point->x = pointx->x;
>     new_point->y = pointy->y;
>
>     PG_RETURN_POINT_P(new_point);
> }
>
> /* by reference, variable length */
>
> PG_FUNCTION_INFO_V1(copytext);
>
> Datum
> copytext(PG_FUNCTION_ARGS)
> {
>     text     *t = PG_GETARG_TEXT_P(0);
>     /*
>      * VARSIZE is the total size of the struct in bytes.
>      */
>     text     *new_t = (text *) palloc(VARSIZE(t));
>     VARATT_SIZEP(new_t) = VARSIZE(t);
>     /*
>      * VARDATA is a pointer to the data region of the struct.
>      */
>     memcpy((void *) VARDATA(new_t), /* destination */
>            (void *) VARDATA(t),     /* source */
>            VARSIZE(t)-VARHDRSZ);    /* how many bytes */
>     PG_RETURN_TEXT_P(new_t);
> }
>
> PG_FUNCTION_INFO_V1(concat_text);
>
> Datum
> concat_text(PG_FUNCTION_ARGS)
> {
>     text  *arg1 = PG_GETARG_TEXT_P(0);
>     text  *arg2 = PG_GETARG_TEXT_P(1);
>     int32 new_text_size = VARSIZE(arg1) + VARSIZE(arg2) - VARHDRSZ;
>     text *new_text = (text *) palloc(new_text_size);
>
>     VARATT_SIZEP(new_text) = new_text_size;
>     memcpy(VARDATA(new_text), VARDATA(arg1), VARSIZE(arg1)-VARHDRSZ);
>     memcpy(VARDATA(new_text) + (VARSIZE(arg1)-VARHDRSZ),
>            VARDATA(arg2), VARSIZE(arg2)-VARHDRSZ);
>     PG_RETURN_TEXT_P(new_text);
> }
>
>
> the error
>
> in function 'makepoint':
> error: 'Point' undeclared (first use in this function)
> error: (each undeclared identifier is reported only one
> error: for each function it appears in.)
> error: 'pointx' undeclared (first use in ´this function)
> error: 'pointy' undeclared (first use in his fnction)
> error 'new_point' undeclared (first use in his function)
> error: syntax error befre ')' oken
> in function 'copy text':
> error: 'invalid lvalue in assinment
> In function 'concat_text'
> error: invalid lvalue in assignement
> warning no new line at end of file
>
> Please any direction of how to solve the problem
>
> thanks
>

Hi,
Basically gcc has no idea what "Point", "pointx" and etc are. You need
to declare or define those types somewhere before they are actually
used.

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