Using rb_require with rb_protect to embed Ruby in C

Question

I want to use rb_require with rb_protect, as in the following example:

int error;
rb_protect( (VALUE (*)(VALUE))rb_require, (VALUE) "./test", &error);

But when I compile it, I get this error:

passing argument 1 of ‘rb_protect’ from incompatible pointer type [enabled by default]
/usr/include/ruby-1.9.1/ruby/intern.h:357:7: note: expected ‘VALUE (*)(VALUE)’ but argument is of type ‘VALUE (*)(VALUE,  VALUE)’

After searching on Google to see how to use rb_require with rb_protect, I tried:

int error;
rb_protect( RUBY_METHOD_FUNC(rb_require), (VALUE) "./test", &error);

or

VALUE require_wrap(VALUE arg)
{
return rb_require("./test");
}
/*in main:*/
rb_protect( require_wrap, 0, & error);

But I always get the same error. This error doesn't stop the compilation but the binary segfault when I launch it whereas everything works without the rb_protect.

__Edit__

there was an error in my source file. In fact all the solutions I have tested works well:

int error;
rb_protect( (VALUE (*)(VALUE))rb_require, (VALUE) "./test", &error);

or

int error;
rb_protect( RUBY_METHOD_FUNC(rb_require), (VALUE) "./test", &error);

or

VALUE require_wrap(VALUE arg)
{
  return rb_require("./test");
}
/*in main:*/
rb_protect( require_wrap, 0, & error);

Thanks

Answer 1

Solutions that works well:

int error;
rb_protect( (VALUE (*)(VALUE))rb_require, (VALUE) "./test", &error);

or

int error;
rb_protect( RUBY_METHOD_FUNC(rb_require), (VALUE) "./test", &error);

or

VALUE require_wrap(VALUE arg)
{
  return rb_require("./test");
}
/*in main:*/
rb_protect( require_wrap, 0, & error);