Obtain Model Identifier string on macOS

Every Mac has a model identifier, for example "Macmini5,1". (These are shown in the System Information app.)

How can I programatically obtain this model identifier string?

You can use sysctl

#import <Foundation/Foundation.h>
#import <sys/sysctl.h>

NSString *ModelIdentifier()
{
    NSString *result=@"Unknown Mac";
    size_t len=0;
    sysctlbyname("hw.model", NULL, &len, NULL, 0);
    if (len) {
        NSMutableData *data=[NSMutableData dataWithLength:len];
        sysctlbyname("hw.model", [data mutableBytes], &len, NULL, 0);
        result=[NSString stringWithUTF8String:[data bytes]];
    }
    return result;
}