catch() - catch an evaluation error

mixed catch( mixed expr );

Evaluate  <expr>.  If  there  is no error, 0 is returned. If there is a
standard error, a string (with a leading '*') will be returned.

The function throw() can also be used to immediately return any  value,
except 0. catch() is not really a function call, but a directive to the
compiler.

The catch() is somewhat costly, and should not be used  just  anywhere.
Rather, use it at places where an error would destroy consistency.

void example1() {
    object ob ;
    mixed err ;

    err = catch( ob = load_object("/obj/weapon/sword") ) ;
    if(err) throw("There was an error loading the specified file.") ;
}

void example2() {
    mixed err = catch {
        string file, *files = ({
            "/u/g/gesslar/one",     // good file
            "/u/g/gesslar/two",     // bad file
            "/u/g/gesslar/three",   // good file
        }) ;

        foreach(file in files) load_object(file) ;
    } ;
    
    if(err) printf("ERR: %O", err) ;
}

// ERR: "*Error in loading object '/u/g/gesslar/two'"

error(3), throw(3), error_handler(4)