Cannot build with OpenCL

[mohd-akram]

ImageMagick version

6.9.12-97

Operating system

MacOS

Operating system, version and so on

13.6

Description

I'm unable to build ImageMagick 6 with OpenCL. I get this error:

magick/opencl.c:3043:16: error: call to undeclared function 'lt_dlclose'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
        (void) lt_dlclose(OpenCLLib->base);
               ^
magick/opencl.c:3043:16: note: did you mean 'dlclose'?
/Library/Developer/CommandLineTools/SDKs/MacOSX13.sdk/usr/include/dlfcn.h:64:12: note: 'dlclose' declared here
extern int dlclose(void * __handle) __DYLDDL_DRIVERKIT_UNAVAILABLE;
           ^
1 error generated.

Adding #include "ltdl.h" to opencl.c (as in ImageMagick 7) resolves the issue. It's not clear if the usage of lt_dlclose should also be conditional based on MAGICKCORE_LTDL_DELEGATE (it is unconditional in v7 as well).

Steps to Reproduce

1. ./configure --enable-opencl
2. make

Images

No response

[urban-warrior]

Thanks for the problem report. We can reproduce the issue and will have a patch to fix it in the GIT main branch @ https://github.com/ImageMagick/ImageMagick later today. The patch will be available in the beta releases of ImageMagick @ https://imagemagick.org/archive/beta/ by sometime tomorrow.

[mohd-akram]

@urban-warrior Thanks. For the main v7 branch it builds fine as it is (the header is already present). I thought that perhaps lt_dlclose shouldn't be used if ltdl isn't available, but it seems ltdl is currently required for OpenCL support, so it doesn't matter at the moment.

The commit 7a828b0 added to v6 seems to have included an extra #if defined(MAGICKCORE_OPENCL_SUPPORT) without a matching #endif. There's already such an ifdef a few lines below, so I think the ltdl section can simply be moved inside it.

[mohd-akram]

I can confirm this works with the new release. Thanks!