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Re: "undefined reference" error when compiling extension functions

From: "Mark Miller" <mark(at)maxpreps(dot)com>
To: <pgsql-hackers-win32(at)postgresql(dot)org>
Subject: Re: "undefined reference" error when compiling extension functions
Date: 2005-04-25 22:55:23
Message-ID: 20050425225815.4242F536BE@svr1.postgresql.org (view raw or flat)
Thread:
Lists: pgsql-hackers-win32
Thanks,

I have to say that it is worlds different than what I'm used to. But it's
never stopped me before ;). I did find why it was pointing to the wrong dir,
the pgxs/src/Makefile.global had the following line in it:

prefix := /usr/local/pgsql

Which likely has something to do with the build, since I did a windows
install the default might not get set. I did set prefix when I ran configure
and make install, but since I only installed includes it make sense that the
file didn't get updated. But sadly, even though I found this and the output
has changed (see below), it did not fix the problem. It still fails with the
following error:

cannot find -lpostgres

Which brings us back to your suggestion of a clean build from scratch. It
seems the only solution unless I want to walk thru every possible place
where I'll run into these problems.

What is "-lpostgres" anyway?

--------------------- make output --------------------------------------

$ make
dlltool --export-all --output-def filesize.def filesize.o
dllwrap -o filesize.dll --def filesize.def filesize.o
c:/Progra~1/PostgreSQL/8.0/lib/pgxs/src/makefiles/../../src/utils/dllinit.o
-L/c/progra~1/postgresql/8.0/bin -lpostgres
c:\MinGW\bin\..\lib\gcc-lib\mingw32\3.2.3\..\..\..\..\mingw32\bin\ld.exe:
cannot find -lpostgres
c:\MinGW\bin\dllwrap.exe: c:\MinGW\bin\gcc exited with status 1
make: *** [filesize.dll] Error 1

------------------------------------------------------------------------


-----Original Message-----
From: Andrew Dunstan [mailto:andrew(at)dunslane(dot)net] 
Sent: Monday, April 25, 2005 3:47 PM
To: mark(at)maxpreps(dot)com
Cc: pgsql-hackers-win32(at)postgresql(dot)org
Subject: Re: [pgsql-hackers-win32] "undefined reference" error when
compiling extension functions


Well, you picked a difficult target to learn on :-)

If you look in pgxs.mk you will see some clues.  You might need to set 
something to point to the installed lib directory (Maybe SHLIB_LINK ?). 
some value like -L/c/progra~1/postgresql/8.0/lib

And if you are coming from Windows build experience and think all this 
has rough edges, you're right, it does.

cheers

andrew

Mark Miller wrote:

>You're right, I could just install it there. That's the easiest way around
>it. But I WOULD like to know why it's mapping to the wrong directory and
how
>to work around it. It would be better if I could install it where ever I
>like. I'm doing this all as a learning experince. Since I have no
experience
>with any of these technologies (C, postgresql, gcc, makefiles), I just want
>to figure out how to do it right.
>
>Thanks,
>Mark
>
>-----Original Message-----
>From: Andrew Dunstan [mailto:andrew(at)dunslane(dot)net] 
>Sent: Monday, April 25, 2005 3:15 PM
>To: mark(at)maxpreps(dot)com
>Subject: Re: [pgsql-hackers-win32] "undefined reference" error when
>compiling extension functions
>
>Install instead to
>
>C:\MSYS\1.0\local\pgsql - under MSys that will map to /usr/local/pgsql
>
>Personally, if I were building extensions I would have built/installed pg
>from scratch, rather than using the installer.
>
>cheers
>
>andrew
>
>
>Mark Miller wrote:
>
>  
>
>>Thanks, that simplifies things.
>>
>>But I ran into the following problem:
>>
>>$ make
>>dlltool --export-all --output-def filesize.def filesize.o
>>dllwrap -o filesize.dll --def filesize.def filesize.o
>>c:/Progra~1/PostgreSQL/8.0/lib/pgxs/src/makefiles/../../src/utils/dllinit.
o
>>-L/usr/local/pgsql/bin -lpostgres
>>c:\MinGW\bin\..\lib\gcc-lib\mingw32\3.2.3\..\..\..\..\mingw32\bin\ld.exe:
>>cannot find -lpostgres
>>c:\MinGW\bin\dllwrap.exe: c:\MinGW\bin\gcc exited with status 1
>>make: *** [filesize.dll] Error 1
>>
>>
>>Here's the makefile (located in /home/usr/dev (windows path is:
>>C:\MSYS\1.0\home\mark\dev)  ***:
>>
>>
>>MODULES = filesize
>>
>>PGXS := $(shell pg_config --pgxs)
>>include $(PGXS)
>>
>>*** ( postgresql is installed in C:\Progra~1\postgresql\8.0\)
>>
>>It looks like "-L/usr/local/pgsql/bin -lpostgres" is looking in the wrong
>>directory. I reinstalled making sure I used the --prefix parameter for
>>configure, but it's still looking in the wrong place. How do I point it to
>>the right "bin" directory?.
>>
>>Again, I did a windows install followed by using MinGW and MSYS to install
>>the headers needed for development. (The reason for doing separate
installs
>>was so I could install PostgreSQL as a service and make sure the proper
>>accounts were set up).
>>
>>Thanks again for your help,
>>Mark
>>
>>
>>-----Original Message-----
>>From: Andrew Dunstan [mailto:andrew(at)dunslane(dot)net] 
>>Sent: Monday, April 25, 2005 2:05 PM
>>To: mark(at)maxpreps(dot)com
>>Cc: pgsql-hackers-win32(at)postgresql(dot)org
>>Subject: Re: [pgsql-hackers-win32] "undefined reference" error when
>>compiling extension functions
>>
>>
>>You might find using the pgxs setup, new in 8.0, useful. See 
>>http://www.postgresql.org/docs/current/static/xfunc-c.html#XFUNC-C-PGXS
>>
>>cheers
>>
>>andrew
>>
>>Mark Miller wrote:
>>
>> 
>>
>>    
>>
>>>I am trying to figure out how to write extension functions and I am 
>>>getting "undefined reference" errors when I compile on the lines which 
>>>call "malloc" and "pfree". How can I get the compiler to see the 
>>>functions so I can compile successfully?
>>>
>>>I installed PostgreSQL on XP Pro using the windows installer, then I 
>>>installed the includes (which are not part of the windows install) by 
>>>running the following commands:
>>>
>>>configure --without-zlib 
>>>--includedir=/c/progra~1/postgresql/8.0/include 
>>>--with-includes=/c/progra~1/postgresql/8.0/include/port/win32/*
>>>
>>>make -C src/include install
>>>
>>>Here's the output from make when I try to compile:
>>>
>>>$ make makefile filesize.dll
>>>
>>>make: Nothing to be done for `makefile'.
>>>
>>>gcc -g -I c:/Progra~1/PostgreSQL/8.0/include -I 
>>>c:/Progra~1/PostgreSQL/8.0/include/server -I 
>>>c:/Progra~1/PostgreSQL/8.0/include/server/port/win32 -I 
>>>c:/Progra~1/PostgreSQL/8.0/lib -fpic -c filesize.c
>>>
>>>cc1.exe: warning: -fpic ignored for target (all code is position 
>>>independent)
>>>
>>>gcc -g -I c:/Progra~1/PostgreSQL/8.0/include -I 
>>>c:/Progra~1/PostgreSQL/8.0/include/server -I 
>>>c:/Progra~1/PostgreSQL/8.0/include/server/port/win32 -I 
>>>c:/Progra~1/PostgreSQL/8.0/lib -shared -o filesize.dll filesize.o
>>>
>>>filesize.o(.text+0x1a): In function `filesize':
>>>
>>>C:/msys/1.0/home/mark/dev/filesize.c:9: undefined reference to 
>>>`pg_detoast_datum'
>>>
>>>filesize.o(.text+0x3d):C:/msys/1.0/home/mark/dev/filesize.c:11: 
>>>undefined reference to `_imp__CurrentMemoryContext'
>>>
>>>filesize.o(.text+0x44):C:/msys/1.0/home/mark/dev/filesize.c:11: 
>>>undefined reference to `MemoryContextAlloc'
>>>
>>>filesize.o(.text+0x9b):C:/msys/1.0/home/mark/dev/filesize.c:19: 
>>>undefined reference to `pfree'
>>>
>>>filesize.o(.text+0xb1):C:/msys/1.0/home/mark/dev/filesize.c:25: 
>>>undefined reference to `pfree'
>>>
>>>make: *** [filesize.dll] Error 1
>>>
>>>Here's the source I'm trying to compile (taken from PostgreSQL ch 6 by 
>>>Douglas and Douglas):
>>>
>>>#include "postgres.h"
>>>
>>>#include "fmgr.h"
>>>
>>>#include <sys/stat.h>
>>>
>>>PG_FUNCTION_INFO_V1(filesize);
>>>
>>>Datum filesize(PG_FUNCTION_ARGS)
>>>
>>>{
>>>
>>>text * fileNameText = PG_GETARG_TEXT_P(0);
>>>
>>>size_t fileNameLen = VARSIZE( fileNameText ) - VARHDRSZ;
>>>
>>>char * fileName = (char *)palloc( fileNameLen + 1 );
>>>
>>>struct stat statBuf;
>>>
>>>memcpy( fileName, VARDATA( fileNameText), fileNameLen );
>>>
>>>fileName[fileNameLen] = '\0';
>>>
>>>if( stat(fileName, &statBuf) == 0 && S_ISREG(statBuf.st_mode) )
>>>
>>>{
>>>
>>>pfree( fileName );
>>>
>>>PG_RETURN_INT32((int32)statBuf.st_size);
>>>
>>>}
>>>
>>>else
>>>
>>>{
>>>
>>>pfree( fileName );
>>>
>>>PG_RETURN_NULL();
>>>
>>>}
>>>
>>>}
>>>
>>>Here's the makefile, from the same example but modified to include the 
>>>needed include directories and to output ".dll" file instead of ".so".
>>>
>>># File name: makefile
>>>
>>>SERVER_INCLUDES += -I $(shell pg_config --includedir)
>>>
>>>SERVER_INCLUDES += -I $(shell pg_config --includedir-server)
>>>
>>>SERVER_INCLUDES += -I $(shell pg_config --includedir-server)/port/win32
>>>
>>>SERVER_INCLUDES += -I $(shell pg_config --libdir)
>>>
>>>CFLAGS += -g $(SERVER_INCLUDES)
>>>
>>>.SUFFIXES: .dll
>>>
>>>.c.dll:
>>>
>>>$(CC) $(CFLAGS) -fpic -c $<
>>>
>>>$(CC) $(CFLAGS) -shared -o $@ $(basename $<).o
>>>
>>>   
>>>
>>>      
>>>
>> 
>>
>>    
>>
>
>
>---------------------------(end of broadcast)---------------------------
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>  
>


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