unable to build against apr -- undefined reference to `apr_initialize'

[Steve Halasz]

I'm trying to compile the following program in oneiric:

#include <apr.h>
#include <apr_general.h>
#include <apr_pools.h>
#include <apr_file_info.h>
#include <apr_file_io.h>
#include <stdlib.h>

int main(int argc, char *argv[]) {
    apr_pool_t *pool;
    apr_file_t *out;

    apr_initialize();
    //atexit(apr_terminate());

    apr_pool_create(&pool, NULL);
    apr_file_open_stdout(&out, pool);
    apr_file_printf(out, "Hello World\n");
    apr_pool_destroy(pool);

    return EXIT_SUCCESS;
}

$ gcc -Wall $(apr-1-config --cflags --cppflags --includes --link-ld) test2.c -o test
/tmp/ccmjrPSw.o: In function `main':
test2.c:(.text+0x10): undefined reference to `apr_initialize'
test2.c:(.text+0x2b): undefined reference to `apr_pool_create_ex'
test2.c:(.text+0x3e): undefined reference to `apr_file_open_stdout'
test2.c:(.text+0x54): undefined reference to `apr_file_printf'
test2.c:(.text+0x60): undefined reference to `apr_pool_destroy'
collect2: ld returned 1 exit status

This works fine in maverick.

$ apr-1-config --cflags --cppflags --includes --link-ld
  -pthread -DLINUX=2 -D_REENTRANT -D_GNU_SOURCE -I/usr/include/apr-1.0 -L/usr/lib -lapr-1

$ lsb_release -rd
Description: Ubuntu 11.10
Release: 11.10

$ apt-cache policy apache2-prefork-dev
apache2-prefork-dev:
  Installed: 2.2.20-1ubuntu1
  Candidate: 2.2.20-1ubuntu1
  Version table:
 *** 2.2.20-1ubuntu1 0
        500 http://us-east-1.ec2.archive.ubuntu.com/ubuntu/ oneiric/main amd64 Packages
        100 /var/lib/dpkg/status

[Steve Halasz (skh2)]

This works fine in natty I meant to say.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[tititou (christophe-jaillet)]

Hi,

I was having the same kind of problem with Ubuntu 12.04 LTS.

After 3 evenings searching for a solution, I reached the online help of gcc about link option (http://gcc.gnu.org/onlinedocs/gcc/Link-Options.html)

There you can read:
>>>>>>>
-l library
It makes a difference where in the command you write this option; the linker searches and processes libraries and object files in the order they are specified. Thus, `foo.o -lz bar.o' searches library `z' after file foo.o but before bar.o. If bar.o refers to functions in `z', those functions may not be loaded.
>>>>>>>

So, try to do:
     gcc -Wall test2.c $(apr-1-config --cflags --cppflags --includes --link-ld) -o test
That is to say, your C file before the APR stuff.
Doing so, -lapr-1 will be at the end of the command line and the linker will find the reference, as per gcc's comment above.

It worked for me.
Hope this can help.

[Steve Halasz (skh2)]

Hi Christophe,

That worked great. Thank you!!