Re: Custom C function - is palloc broken?

Craig Ringer wrote:
> Can you send me a complete, compileable example that illustrates the
> problem, along with instructions on how to reproduce it? If possible,
> send a compiled binary and any dependencies too. I'm curious to see if
> this is in fact shared library issues.

I'll send you a .zip file separately with the actual code, but here are
the steps I took:

- Install Postgres 8.3.1
- Install MinGW 5.1.4
- Install the gettext snapshot from MinGW's downloads page under "snapshots"

Then, unzip the zip file I'll send you. Make sure MinGW's bin directory
is in your windows PATH environment variable. In a command prompt, go
to your unzipped directory and run mingw32-make. The makefile I've
included will put the .dll in Postgres' lib/plugins directory (assuming
you installed postgres in its default location - modify the makefile if
that is not the case).

Once the .dll is ready, I created the function in Postgres using the
CREATE FUNCTION command given in the documentation, modified slightly:

CREATE FUNCTION copytext(text) RETURNS text
AS '$libdir/plugins/mylib.dll', 'copytext'
LANGUAGE C STRICT;

Then I used the following SELECT statement:

SELECT copytext(colname) FROM tablename;

where "colname" is a text column in table "tablename". This statement
crashes the database server.

I read somewhere on Postgres' website that the win32 binaries were built
with MinGW - and in fact they must be, since MSVC++ does not have some
of the unix headers needed to build Postgres.

Your theory could very well be true - especially if the issue is with a
different version of gettext. MinGW's website's snapshot is from 2006
or something, so it wouldn't surprise me if Postgres uses a newer version.

A zip file is attached to a separate e-mail to you. Anyone else who
would like a copy may have one, just let me know, but it's basically
just the copytext example from the tutorials pasted into a .c file, and
a makefile.

- Dan