C API design: Who should allocate? [closed]

Answer 1

See your method #2 says

myStruct *s = myStruct_init();

myStruct_foo(s);

myStruct_destroy(s);

Now see if myStruct_init() needs return some error code for various reason then lets go this way.

myStruct *s;
int ret = myStruct_init(&s);  // int myStruct_init(myStruct **s);

myStruct_foo(s);

myStruct_destroy(s);