dynamic loading of the imagemagic library?

dynamic loading of the imagemagic library?

[joakim]

Currently the imagemagick patch uses ordinary linking to the run-time
library file. Looking at image.c, w32 seems to check in runtime if other
image libraries are present, this is not done for gnu/linux AFAICS.

Is it ok to use dlopen and dlsym for imagemagick loading on
gnu/linux platforms? I presume yes, but since I only dimly understand
why dynamic use of external libraries is problematic, I ask.

-- 
Joakim Verona

Re: dynamic loading of the imagemagic library?

[Jason Rumney]

joakim@verona.se wrote:
> Is it ok to use dlopen and dlsym for imagemagick loading on
> gnu/linux platforms? I presume yes, but since I only dimly understand
> why dynamic use of external libraries is problematic, I ask.
>   

Linking to Free libraries is not problematic, making a generalized API 
to allow arbritrary libraries to be dynamically loaded might be.  The 
reason w32 uses dynamic linking for the image libraries is that there is 
no equivalent of apt/deb, rpm, BSD ports or fink on w32, so it is better 
for the users if we don't fail to run when non-essential dependencies 
are missing.

Re: dynamic loading of the imagemagic library?

[joakim]

Jason Rumney <jasonr@gnu.org> writes:

> joakim@verona.se wrote:
>> Is it ok to use dlopen and dlsym for imagemagick loading on
>> gnu/linux platforms? I presume yes, but since I only dimly understand
>> why dynamic use of external libraries is problematic, I ask.
>>   
>
> Linking to Free libraries is not problematic, making a generalized API
> to allow arbritrary libraries to be dynamically loaded might be.  The
> reason w32 uses dynamic linking for the image libraries is that there
> is no equivalent of apt/deb, rpm, BSD ports or fink on w32, so it is
> better for the users if we don't fail to run when non-essential
> dependencies are missing.

Ok, a user expressed interest in having the same system on for instance
Debian, so imagemagick wouldnt be a hard dependency of emacs, just an
optional one. I agree with the sentiment.
-- 
Joakim Verona