Re: Compiling a user C function in 7.2.1

P.S. I forgot to supply the commands I used to compile and link my
bvbpglib.so library:
gcc -O2 -march=i386 -mcpu=i686 -Wall -Wmissing-prototypes
-Wmissing-declarations -fpic
-I/usr/src/redhat/BUILD/postgresql-7.2.1/src/interfaces/libpq
-I/usr/src/redhat/BUILD/postgresql-7.2.1/src/include
-I/usr/kerberos/include -c -o bvbpglib.o bvbpglib.c
gcc -shared -o /usr/include/bvbpglib.so bvbpglib.o

John G

John Gunther wrote:

> Tom Lane wrote:
>
>> (a) you didn't run configure, which creates the files you are missing.
>>
>>
> Thanks, Tom. Your reply caused me to learn a lot about building
> PostgreSQL from source.
>
> Now I'm much further along: I have created a dynamic library
> (bvbpglib.so) containing one PostgreSQL C function (bvbpgsortword).
> This function calls a "regular" (non-PostgreSQL) C function
> (bvbmakesortstring).
>
> My current problem is that my psql statement:
> CREATE FUNCTION bvbpgsortword(TEXT) RETURNS TEXT AS
> '/usr/include/bvbpglib' LANGUAGE C WITH (ISSTRICT);
> fails with "undefined symbol: bvbmakesortstring"
>
> This is probably the result of some fundamental deficit in my
> understanding of C writing/compiling/linking, but what puzzles me is
> that bvbmakesortstring is called successfully from another C program I
> wrote. Only in psql does it come back undefined.
>
> Thanks.
>
> John Gunther
>
> For anyone is interested in enlightening me, relevant source follows:
>
> SOURCE FOR bvbpglib.c (used to create bvbpglib.so, contains PostgreSQL
> function bvbpgsortword):
> #include "postgres.h"
> #include "fmgr.h"
> #include <string.h>
> #include "bvblib.h"
> Datum bvbpgsortword(PG_FUNCTION_ARGS);
> PG_FUNCTION_INFO_V1(bvbpgsortword);
> Datum bvbpgsortword(PG_FUNCTION_ARGS){
> //declarations
> char *bvbmakesortstring(const char *input, const int bitmodes,
> const unsigned short int minlength, const char *keeplist, const char
> *outdelim, const char *stoplist);
> text *instr = PG_GETARG_TEXT_P(0);
> text *outstr;
> unsigned int length;
> char *target;
> //code
> target=VARDATA(outstr);
> target = bvbmakesortstring(VARDATA(instr),1,0,"","}","");
> length=strlen(target-1);
> target[length]=0;
> VARATT_SIZEP(outstr) = length + VARHDRSZ;
> PG_RETURN_TEXT_P(outstr);
> }
>
> SOURCE FOR test.c (this successfully calls bvbmakesortstring):
> #include <stdio.h>
> #include "bvblib.h"
> int /*function*/ main(){
>
> printf("out=%s\n",bvbmakesortstring("test-mctöst'tëst",0,0,",","=","A"));
> return 0;
> }
>
> PARTIAL SOURCE FOR bvblib.c (this library contains bvbmakesortstring):
> #include <string.h>
> #include "bvblib.h"
> char bvbstr[65535];
> char *bvbmakesortstring(
> const char *instr,
> const int bitmodes,
> const unsigned short int minlength,
> const char *keeplist,
> const char *outdelim,
> const char *stoplist
> )
> {<code>...
> return bvbstr;//return the sort-ready string
> }
>
> SOURCE FOR bvblib.h:
> #ifndef BVBLIB_H /* has this been included */
> #define BVBLIB_H /* if not say its been done once */
> char bvbstr[65535];
> char *bvbmakesortstring(
> const char *instr, //string to be
> processed
> const int bitmodes,
> const unsigned short int minlength, //words shorter than this
> are ignored
> const char *keeplist, //chars
> to be kept in output words
> const char *outdelim, //char
> string to use as word delimiter
> const char *stoplist
> //space-separated words to be ignored
> );
> #endif /* end the #ifndef construct */
>
>
>
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