error: unknown type name 'EXTERN_C'

[Huang-XN]

Hey,

I reproduced this error as it was in #201. But I could not solve it by commenting EXTERN_C void __attribute__((noreturn)).

When I commented it, it produced another error as follow:

In file included from /Users/xxx/Documents/MATLAB/vlfeat-0.9.21/./toolbox/vlad/vl_vlad.c:15:
toolbox/mexutils.h:176:1: warning: type specifier missing, defaults to 'int'; ISO C99 and later do not support implicit int [-Wimplicit-int]
mexErrMsgIdAndTxt (const char * identifier, const char * err_msg, ...) ;
^
int
toolbox/mexutils.h:176:1: error: conflicting types for 'mexErrMsgIdAndTxt'
/Applications/MATLAB_R2021a.app/extern/include/mex.h:159:28: note: previous declaration is here
LIBMWMEX_API_EXTERN_C void mexErrMsgIdAndTxt(
                           ^
1 warning and 1 error generated.

make: *** [toolbox/mex/mexmaci64/vl_vlad.mexmaci64] Error 255

The command I used was make CC=/usr/local/opt/llvm/bin/clang DISABLE_OPENMP=no MEX=/Applications/MATLAB_R2021a.app/bin/mex ARCH=maci64

I am using MacOS BigSur 11.5.1 and MATLAB R2021a.

Can anyone solve it?

Thanks

Huang

[VishalP227]

I was getting the same error after commenting the line. It looks like EXTERN_C is a mistake, I changed it to just 'extern', what I mean is on line 175 of mexutils.h file I changed is from

EXTERN_C void attribute((noreturn))

to this :

extern void attribute((noreturn))

After doing this and running the make command again it was able to compile successfully.
I hope this helps.