c++macosubuntumime-typeslibmagic

46: regex error 17 for `(dryad-bibo/v)[0-9].[0-9]', (match failed)

I'm trying to determine the mime-type for several types of files using libmagic and the following bit of code:

auto handle = ::magic_open(MAGIC_MIME_TYPE);
::magic_load(handle, NULL);

// Both of these fail with the same error
// file_path being a const char* with the path to the file.
auto type2 = ::magic_file(handle, file_path);

// svg_content being an std::vector<char> with the contents of the file.
//auto type2 = ::magic_buffer(handle, svg_content.data(), svg_content.size()); 

if(!type2)
{
   std::cout << magic_error(handle) << std::endl;
}
    
::magic_close(handle);

But for any file or buffer I try I receive regex error, either being or similar to:

46: regex error 17 for `(dryad-bibo/v)[0-9].[0-9]', (match failed)

For example with this .svg file:

<svg xmlns="http://www.w3.org/2000/svg" id="flag-icon-css-no" viewBox="0 0 640 480">
  <path fill="#ed2939" d="M0 0h640v480H0z"/>
  <path fill="#fff" d="M180 0h120v480H180z"/>
  <path fill="#fff" d="M0 180h640v120H0z"/>
  <path fill="#002664" d="M210 0h60v480h-60z"/>
  <path fill="#002664" d="M0 210h640v60H0z"/>
</svg>

What I've tried so far:

I'm linking against a version of libmagic that was built locally, could there be anything I have missed while building? Are any of the calls incorrect or is there something I'm missing?

I get similar errors when trying to run the related file binary that was compiled locally. Whereas when I use the file command that is available by default I do get image/svg+xml as output.

Edit

To build libmagic (for macOS and Ubuntu), I followed these steps:

Update

It looks like the regex at the bottom of this file is causing issues (at least for the svg):

https://github.com/file/file/blob/b56b58d499dbe58f2bed28e6b3c297fe7add992e/magic/Magdir/dataone

Update 2

Something strange going on; On the system where I've got it working, magic_version() reports 540, as expected. But on the systems where it fails with this error, magic_version() reports 538.

This makes little sense to me as I can't find that version on the system itself anywhere and when I run ./file --version in the build library, it reports file-5.40.

Solution

  • Very dissatisfying answer, but it was linking against GoogleTest causing this error somehow, not even running any tests, just linking against it.

    I switched to using Catch2 instead and the issue was resolved.