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Accepted
Mike Purcell
Asked: 2012-05-11 16:48:41 +0800 CST

CentOS 6 - Make system aware of custom lib paths and missing base links

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I am trying to compile libmemcached (1.0.7) on CentOS6, and keep getting the following warning:

...
checking for event.h... no
configure: WARNING: Unable to find libevent
...

I manually compiled libevent (2.0.19) and built it using the following configure line:

OPTIONS="--prefix=/usr/local/_custom/app/libevent"

Everything compiled and installed fine, but I couldn't figure out how to make the system aware that the lib files are in the custom /usr/local/_custom/app/libevent/libdir. I stumbled upon an article and read that I can make the system aware of custom lib paths by adding a custom file to /etc/ld.so.conf.d/ directory:

# /etc/ld.so.conf.d/customApp.conf
/usr/local/_custom/app/libevent/lib

Then I issued the ldconfig command and was able to confirm that libevent was included by issuing this command:

ldconfig -p | ack -i libevent

Seeing that libevent was now included in the ldconfig output, I figured I would be able to compile libmemcached and satisfy the aforementioned warning. Unfortunately it did not. So I took another look at the ldconfig output and noticed this:

libevent_pthreads-2.0.so.5 (libc6,x86-64) => /usr/local/_custom/app/libevent/lib/libevent_pthreads-2.0.so.5
libevent_openssl-2.0.so.5 (libc6,x86-64) => /usr/local/_custom/app/libevent/lib/libevent_openssl-2.0.so.5
libevent_extra-2.0.so.5 (libc6,x86-64) => /usr/local/_custom/app/libevent/lib/libevent_extra-2.0.so.5
libevent_core-2.0.so.5 (libc6,x86-64) => /usr/local/_custom/app/libevent/lib/libevent_core-2.0.so.5
libevent-2.0.so.5 (libc6,x86-64) => /usr/local/_custom/app/libevent/lib/libevent-2.0.so.5

There are no references to the base links, for example, I would expect to see links to these (ls -la /usr/local/_custom/app/libevent/lib):

libevent.so -> libevent-2.0.so.5.1.7
libevent_openssl.so -> libevent_openssl-2.0.so.5.1.7
libevent_core.so -> libevent_core-2.0.so.5.1.7

So either I am doing something wrong, or the system still does not know where to look to find libevent.so.

-- Update #1 --

I wasn't able to get libmemcached to compile without the warning notice, even after trying to compile using the following configure command:

./configure --prefix=/usr/local/_custom/app/libmemcached CFLAGS="-I/usr/local/_custom/app/libevent/include" LDFLAGS="-L/usr/local/_custom/app/libevent/lib"

I thought for sure this would work because I am directly passing the include and lib directories to the configure command. But it did not.

centos6

5 Answers

  1. Sorry for my english first. my os: CentOS 6.3 mini without desktop x86_64, i haven't yum install libevent i met same problem many times in different environment Here is my installation process of libevent:

    tar zxvf libevent-2.0.20-stable.tar.gz
cd libevent-2.0.20-stable
./configure --prefix=/usr/local/libevent
make
make install

    before my install libmemcached-1.0.10 i tried 

    ./configure --prefix=/usr/local/libmemcached --with-lib-prefix=/usr/local/libevent --with-memcached=/usr/local/bin/

    and

    LIBEVENT_CPPFLAGS=/usr/local/libevent/include
LIBEVENT_LDFLAGS=/usr/local/libevent/lib

    the problem also happend. then i do some link like here:

    ln -s /usr/local/libevent/include/* /usr/include/
ln -s /usr/local/libevent/lib/libevent* /usr/lib64/

    it's done! i think libmemcached locate libevent.so and event.h has some hard code. wish my solution can help u.

    • 4

  2. I was going to suggest installing the libevent-devel package on the system. That will provide the header file listed in the error you posted, but the version may be older (1.4.13-1) than what you need for your libmemcached.

    Looking at your sequence, I'd actually recommend removing the config.cache file in your libmemcached source directory, then rerunning the ./configure for libmemcached. That should allow the process to recognize the changes you made to the library search paths.

    • 2
  3. Best Answer

    I had the same issue and was about to give up on libmemcached when I noticed that the configure flag should be 

    CPPFLAGS="-I/usr/local/_custom/app/libevent/include"

    instead of 

    CFLAGS="-I/usr/local/_custom/app/libevent/include"
    • 1

  4. After speaking with a few seasoned Sysadmin guys from work, I opted to just do a yum install memcached. As with CentOS, one of the trade-offs is working with older versions of apps/libs, but CentOS maintainers will backport security fixes etc, so I figured I'll just go with the upstream version and save myself some headache.

    • 0

  5. Well, I don't have a proper answer, but I did notice when my freshly compiled tmux on CentOS told me 

    tmux: error while loading shared libraries: libevent-2.0.so.5: cannot open shared object file: No such file or directory

    I tried this, and it worked: 

    LD_LIBRARY_PATH=/usr/local/lib tmux

    I'm not sure what the canonical/standard way of setting the system's LD_LIBRARY_PATH is, but it does not appear to be "horrible" per se if I stuck it into bashrc/zshrc.

    Edit: Ah, here is one answer that elucidates the way to tell your system where the libraries live.

    • 0