static libraries

eteck · 11-03-2010, 12:13 AM

Hi,

I have a libX.a that I've created (from test.c) and put in /usr/lib/

I've then created another libY.a, that calls functions in libX.a, I've also copied this lib to /usr/lib/

Now when I write a program that uses both these libs, then compile I get:

Code:

bill@micosoftsux:~$ gcc test_prog.c  -Wall -m32 -O -g -lX -lY -o test_prog
/usr/lib/libY.a(test.c.o): In function `test_init':
test.c:(.text+0x111): undefined reference to `test_open'
test.c:(.text+0x237): undefined reference to `test_open'
/usr/lib/libY.a(test.c.o): In function `test_send':
test.c:(.text+0x7e3): undefined reference to `test_write'
test.c:(.text+0x8fc): undefined reference to `test_write'
collect2: ld returned 1 exit status
make: *** [test_prog] Error 1

test.c header files exist in /usr/include/ and I've compiled with -lX -lY, but its not working...

Any ideas?

Dark_Helmet · 11-03-2010, 12:29 AM

I don't mess with static libraries, but from man gcc:

Code:

   Options for Linking
       These options come into play when the compiler links object files into
       an executable output file.  They are meaningless if the compiler is not
       doing a link step.

       ...

       -static
           On systems that support dynamic linking, this prevents linking with
           the shared libraries.  On other systems, this option has no effect.

eteck · 11-03-2010, 12:40 AM

Well if you don't make static lib's you have not lived. Anyway changed the order of the -l and it worked fine.

neonsignal · 11-03-2010, 08:39 AM

Quote:

Originally Posted by eteck

Anyway changed the order of the -l and it worked fine.

Yes, you have to put the libraries with the calling functions in the list before the libraries with the functions that they call.

When the linker loads in a library, it only includes the functions that are required (which is the whole reason for using a library rather than an object file). However, it can only tell that functions are required if they have already been used in previous object files or libraries, since the linking is done in a single pass.