xcode - Connect iPhone App to PostgreSQL Using Libpq

Question

I need to create an application for the iPhone that will connect to a PostgreSQL 8.4 database using libpq. The problem is I can't get a simple iPhone that links to libpq to compile. I am however able to get the equivalent application that is a regular Mac desktop app to compile and connect to PostgreSQL without any issues. I'm on Xcode 3.2 running on Snow Leopard.

I'm building libpq for both arm and for x86_84. The arm build is for the real iPhone and the x86_64 is for the iPhone simulator to use. I then create a fat binary that contains both files and end up with a file named libpq. This file is the one I use in the regular Mac app and it works fine and causes issues when trying to build the iPhone app.

Here is my build script when I build libpq.

#!/bin/bash

DEVROOT=/Developer/Platforms/iPhoneOS.platform/Developer
SDKROOT=$DEVROOT/SDKs/iPhoneOS3.0.sdk

rm -rf  /Users/bob/mylibs
mkdir /Users/bob/mylibs #Store there compiled libs
make clean

#Build ARM library
./configure --host=arm-apple-darwin --without-readline --disable-ipv6 CC=$DEVROOT/usr/bin/arm-apple-darwin9-gcc-4.0.1 CPPFLAGS="-I$SDKROOT/usr/lib/gcc/arm-apple-darwin9/4.0.1/include/ -I$SDKROOT/usr/include/" CFLAGS="$CPPFLAGS -arch armv6 -pipe -no-cpp-precomp -isysroot $SDKROOT" CPP="$DEVROOT/usr/bin/cpp $CPPFLAGS" LD=$DEVROOT/usr/bin/ld
make -C src/interfaces/libpq
cp /Users/bob/Downloads/postgresql-8.4.1/src/interfaces/libpq/libpq.a /Users/bob/mylibs/libpq.arm

#Then build i386 library
make clean && ./configure  && make -C src/interfaces/libpq
cp src/interfaces/libpq/libpq.a  /Users/bob/mylibs/libpq.i386

#Then make fat binary
$DEVROOT/usr/bin/lipo -arch armv6 /Users/bob/mylibs/libpq.arm -arch x86_64 /Users/bob/mylibs/libpq.i386 -create -output  /Users/bob/mylibs/libpq

Here is the build log when I try to compile the iPhone app from within Xcode.

Build iPhonePg of project iPhonePg with configuration Debug

Ld build/Debug-iphonesimulator/iPhonePg.app/iPhonePg normal i386
cd /Users/bob/Documents/Programming/PragProgrammerIphoneSDK/iPhonePg
setenv MACOSX_DEPLOYMENT_TARGET 10.5
setenv PATH "/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin/gcc-4.2 -arch i386 -isysroot /Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator3.0.sdk -L/Users/bob/Documents/Programming/PragProgrammerIphoneSDK/iPhonePg/build/Debug-iphonesimulator -L../../../../mylibs -L/Users/bob/Documents/Programming/PragProgrammerIphoneSDK/iPhonePg -L/Users/bob/Documents/Programming/PragProgrammerIphoneSDK/iPhonePg/../../../../mylibs -F/Users/bob/Documents/Programming/PragProgrammerIphoneSDK/iPhonePg/build/Debug-iphonesimulator -filelist /Users/bob/Documents/Programming/PragProgrammerIphoneSDK/iPhonePg/build/iPhonePg.build/Debug-iphonesimulator/iPhonePg.build/Objects-normal/i386/iPhonePg.LinkFileList -mmacosx-version-min=10.5 -framework Foundation -framework UIKit -framework CoreGraphics /Users/bob/Documents/Programming/PragProgrammerIphoneSDK/iPhonePg/libpq -o /Users/bob/Documents/Programming/PragProgrammerIphoneSDK/iPhonePg/build/Debug-iphonesimulator/iPhonePg.app/iPhonePg

ld: warning: in /Users/bob/Documents/Programming/PragProgrammerIphoneSDK/iPhonePg/libpq, missing required architecture i386 in file
Undefined symbols:
  "_PQclear", referenced from:
      -[iPhonePgAppDelegate applicationDidFinishLaunching:] in iPhonePgAppDelegate.o
  "_PQerrorMessage", referenced from:
      -[iPhonePgAppDelegate applicationDidFinishLaunching:] in iPhonePgAppDelegate.o
  "_PQconnectdb", referenced from:
      -[iPhonePgAppDelegate applicationDidFinishLaunching:] in iPhonePgAppDelegate.o
  "_PQfinish", referenced from:
      -[iPhonePgAppDelegate applicationDidFinishLaunching:] in iPhonePgAppDelegate.o
  "_PQstatus", referenced from:
      -[iPhonePgAppDelegate applicationDidFinishLaunching:] in iPhonePgAppDelegate.o
  "_PQexec", referenced from:
      -[iPhonePgAppDelegate applicationDidFinishLaunching:] in iPhonePgAppDelegate.o
ld: symbol(s) not found
collect2: ld returned 1 exit status

Anyone else run into this that can help out?

Thanks StartShip3000

Answer 1

It looks like you are not actually linking in the library. You have added the directory it is in to your search path, but I don't see -lpq anywhere on your link line.

Also, the simulator environment is 32 bit only, x86_64 libs won't work with simulator binaries.