Although Apple recommends bundles be given the extension .bundle many developers give them the .so extension for the sake of cross-platform familiarity. On Linux, no distinction is made between a shared module (a bundle on MacOS) and a shared library (a dylib on MacOS.)
Understanding that, as ld states, you cannot link to an MH_BUNDLE on MacOS. It either needs to be a dylib to link it, or you need to load the .so using the dyld APIs.
This link gives an example of how to dynamically load a bundle on MacOS:
#include <stdio.h>
#import <mach-o/dyld.h>
int main( )
{
int the_answer;
int rc; // Success or failure result value
NSObjectFileImage img; // Represents the bundle's object file
NSModule handle; // Handle to the loaded bundle
NSSymbol sym; // Represents a symbol in the bundle
int (*get_answer) (void); // Function pointer for get_answer
/* Get an object file for the bundle. */
rc = NSCreateObjectFileImageFromFile("libanswer.bundle", &img);
if (rc != NSObjectFileImageSuccess) {
fprintf(stderr, "Could not load libanswer.bundle.\n");
exit(-1);
}
/* Get a handle for the bundle. */
handle = NSLinkModule(img, "libanswer.bundle", FALSE);
/* Look up the get_answer function. */
sym = NSLookupSymbolInModule(handle, "_get_answer");
if (sym == NULL)
{
fprintf(stderr, "Could not find symbol: _get_answer.\n");
exit(-2);
}
/* Get the address of the function. */
get_answer = NSAddressOfSymbol(sym);
/* Invoke the function and display the answer. */
the_answer = get_answer( );
printf("The answer is... %d\n", the_answer);
fprintf(stderr, "%d??!!\n", the_answer);
return 0;
}
