Re: [SQL] Registring a C function in PostgreSQL

[Miguel González]

Many thanks for your answers. The thing that in the Bruce´s book doesnt
explain how to compile this kind of functions, anyway I found how to compile
it.

 Now, I am still having problems. I want to create a function to send an
email. I pass to the function two arguments: the email to send, and the text
to send.

 First, I tried with pointers to char. It worked when I just create a
function called "sendemail()" with no arguments and set inside the text and
the email arguments.

 When I read some more documentation about how to use strings in PostgreSQL,
I discovered that I have to use the text type in my C program I just try it
but
although it worked before, now I doesnt work.

 This is what I have tried:


 #include <stdio.h>
 #include "postgres.h"

 int sendemail(text *email,text *message)
 {

     char string_tosend [300];

     sprintf(string_tosend,"echo \"%s\" >/tmp/mailtmp.txt
\n",VARDATA(message));

     system(string_tosend);

    sprintf(string_tosend,"mail -s \"message from PostgreSQL\" %s
</tmp/mailtmp.txt \n",VARDATA(message));

     system(string_tosend);

     system("rm /tmp/mailtmp.txt");

     return 0;


 }


 and then in the back-end of PostgreSQL and I declared

 CREATE FUNCTION sendemail(text,text)
 RETURNS int4
 AS '/home/postgres/libpginvuimail.so'
 LANGUAGE 'c';

 and then SELECT sendemail('postgres','test from backend');

 and it didnt work. What am I doing wrong?

 I have being testing and I guess is something to do with the text data type
and how to use it within a C program.

 Many thanks in advance

 Miguel







----- Original Message -----
From: "Haller Christoph" <[EMAIL PROTECTED]>
To: "Miguel González" <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Wednesday, September 19, 2001 12:24 PM
Subject: Re: [SQL] Registring a C function in PostgreSQL


> Did you use the compiler option for generating
> position independent code (PIC) for use in building
> shared libraries.
> Did you use the linker option for creating
> a shared library - I think you did, the file
> suffix .so looks that way.
> I did it several times successfully using commands
> like
> CREATE FUNCTION byteatostr(bytea) RETURNS text
>  AS './byteatostr.sl' LANGUAGE 'c';
> and it worked.
> Maybe you should add some more information about
> what you did in detail.
> Regards, Christoph
>


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