Error in xcode project: ld: library not found for -lcrt1.10.6.o

Question

Just upgraded to Snow Leopard, installed Xcode 3.2, then installed iPhone SDK 3 for SL.

In a project, I now get the following error on build:

Answer 1

The compiler normally uses crt1.o combined with crt[i/n].o and crt[begin/end].o to support the constructors and destructors (functions called before and after main and exit).

This error could be caused by this missing library file for the specific deployment target.

First, do some investigation, like:

1. List all your deployment targets:

   ls -la /Developer/SDKs
   

2. Find which crt1 libraries do you have for which environment

   find /Developer/SDKs -name crt1\*
   

   You could see something like:

   /Developer/SDKs/MacOSX10.5.sdk/usr/lib/crt1.10.5.o
   /Developer/SDKs/MacOSX10.5.sdk/usr/lib/crt1.o
   /Developer/SDKs/MacOSX10.6.sdk/usr/lib/crt1.10.5.o
   /Developer/SDKs/MacOSX10.6.sdk/usr/lib/crt1.10.6.o
   /Developer/SDKs/MacOSX10.6.sdk/usr/lib/crt1.o
   

As you can see in above example, crt1.10.6.o is missing for MacOSX10.5.

Solution 1

You can solve that by creating the link to the missing file pointed to the other environment, or you could change your deployment target. E.g.

ln -s /Developer/SDKs/MacOSX10.6.sdk/usr/lib/crt1.10.6.o /Developer/SDKs/MacOSX10.5.sdk/usr/lib/

---

Other reason why it's missing, is that you could have different gcc installed in your system. E.g.:

which gcc
xcrun -find gcc
brew list | grep gcc; brew list gcc47

Solution 2

So when you're compiling using make, you can actually specify the right compiler by CC variable. E.g.

CC=/path/to/gcc-3.4 make

---

Solution 3

What you can also try is specifying the right target deployment environment variable for gcc, e.g.:

export MACOSX_DEPLOYMENT_TARGET=10.5

If this works, then you can add this library path to your shell profile (~/.profile). E.g.

export C_INCLUDE_PATH=/Developer/SDKs/MacOSX10.5.sdk/usr/include

export LIBRARY_PATH=/Developer/SDKs/MacOSX10.5.sdk/usr/lib

Or by temporary exporting them.

---

How to test

Create the example conftest.c file with the following code:

#ifdef __GNUC__
  yes;
#endif

And try to compile it via:

gcc conftest.c
cc conftest.c
cc conftest.cc conftest.c