Imager::Threads - Imager and threads
use Imager; use threads; Imager->preload; threads->create(...);
Starting from version 0.94 Imager attempts to work safely with perl's ithreads.
ithreads
Previous versions stored some state in global variables, in particular the internal error stack.
However there are some limitations:
Imager's debug malloc isn't thread safe and will never be. Imager's debug malloc is disabled by default.
libtiff, which Imager uses for TIFF file support is not thread safe, Imager::File::TIFF works around this by single-threading its access to libtiff.
libtiff
Imager::File::TIFF
giflib, which Imager uses for GIF support is not thread safe before version 5. Imager::File::GIF works around this by single threading its access to giflib.
giflib
Imager::File::GIF
T1Lib, used by one of Imager's font drivers, is not thread safe. Imager::Font::T1 works around this by single threading access.
T1Lib
Imager::Font::T1
killing a thread reading or writing TIFF or GIF files, or using T1 fonts through Imager::Font::T1 may deadlock other threads when they attempt to read or write TIFF or GIF files, or work with Type 1 fonts.
Fill, font, color or I/O layer objects created in one thread are not valid for use in child threads. If you manage to duplicate such an object in another thread, you get to keep both pieces when it breaks.
Note that if you have another module using libtiff, giflib or t1lib it may interact with Imager's use of those libraries in a threaded environment, since there's no way to co-ordinate access to the global information libtiff, giflib and t1lib maintain.
t1lib
Imager currently doesn't use threads itself, except for testing its threads support.
Imager, threads
threads
Tony Cook <tony@cpan.org>
To install Imager, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Imager
CPAN shell
perl -MCPAN -e shell install Imager
For more information on module installation, please visit the detailed CPAN module installation guide.