linux build fixes about pixz

[epitron]

Tested -- this works!

The most crucial fix is the -lpthread under linux, which isn't linked in by default.

[yoshi314]

i'm still having runtime problems, though. It only produces 24byte file or so (if i remember correctly, it's been a while since i tried it).

Could be wrong invocation of the tool, or something wrong on my end.

[epitron]

Works for me under Arch. Maybe your lzma lib was too old.

[yoshi314]

that was also on arch, 64bit. will retest.

[vasi]

yoshi314, the issue with producing a really small file is indeed a wrong invocation. In pixz's default mode, it auto-detects tar files so it can index them, which is useful. BUT a file that starts with 512 zero bytes is in fact a valid, empty tar file, so pixz just stops.

You should run pixz with the -t flag to tell it not to do tar detection. I hope to add at some point a feature to warn on empty tar files, so users don't run into this problem anymore.

[yoshi314]

thanks for info. i'll see if that helps.

[justinmayer]

Hey Dave. You may remember me from an article I wrote about parallel bzip2. I'd like to write a follow-up that covers parallel xz compression, but before I do that I'd like to get pixz functioning properly on Ubuntu 12.04. Here are the exact steps I took:

sudo aptitude install libarchive-dev liblzma-dev
git clone https://github.com/vasi/pixz
cd pixz
make
cp pixz ~/bin/

While it appears to have compiled successfully, there was a warning in the output during compilation:

gcc -I/usr/include -I//include -g -O0 -std=gnu99 -Wall -Wno-unknown-pragmas -c -o pixz.o pixz.c
gcc -I/usr/include -I//include -g -O0 -std=gnu99 -Wall -Wno-unknown-pragmas -c -o common.o common.c
common.c: In function ‘decode_index’:
common.c:247:47: warning: integer overflow in expression [-Woverflow]
[...]

I then compressed a folder of files:

tar -c myfolder | pixz -3 > myfolder.tar.xz

So far so good. But I got an error when testing decompression:

pixz -x myfolder < myfolder.tar.xz | tar -x
Error creating index decoder

Hmm. Perhaps I'll try something simpler:

pixz -d myfolder.tar.xz
Error creating index decoder

Any suggestions as to how to get pixz to function correctly on the most recent version Ubuntu? I tried the modifications @yoshi314 suggested, but the results were the same.

[vasi]

Hi justinmayer. I believe I have it working fine in a VM, so I'm curious what's going on. Could you specify exactly what your Ubuntu install looks like? x86 or amd64? Desktop or Server?

[justinmayer]

Certainly. I did my testing in a (nearly) fresh install of Ubuntu 12.04 Desktop in a VMware Fusion virtual machine. I don't recall whether I installed the x86 or amd64 version, but I suspect it's x86.

[vasi]

Justin, thanks so much for the bug report! It was indeed a problem with x86, I just hadn't tested there. The problem is fixed in the latest commit: ee8a340

Incidentally, I just want to make sure you're aware that in your example "pixz -x myfolder < myfolder.tar.xz" is equivalent to "pixz -d < myfolder.tar.xz" but more complex. The -x flag is used for filtering the output, if you're not doing any filtering it's just redundant. :)

[vasi]

yoshi314, epitron: This latest bout of testing confirms that it compiles fine in Ubuntu. Is Arch still a problem?

I'll look into it, but I'm not inclined to go through the rather complicated Arch install process just to test. I'd greatly appreciate if there's a VM available somewhere that I could test on!

[vasi]

Thanks to thestinger and gtmanfred in #archlinux, this should be fixed in c5f99bf . Sorry it took so long, and thank you for reporting the problem.

[epitron]

Woohoo! :D