mrb_get_args

mrb_get_args

Declaration	Definition
mruby.h	class.c

int mrb_get_args(mrb_state *mrb, const char *format, ...);

Retrieves arguments from a mrb_state.

Parameters

• mrb: mruby VM state

• format: pointer to a null-terminated string.

The following format specifiers are available:

Character	Explanation	Argument type
o	Object	mrb_value*
S	String	mrb_value*
A	Array	mrb_value*
H	Hash	mrb_value*
s	char array (may include null byte!), length	char**, int*
z	null-terminated char array	char**
a	Array (elements, length)	mrb_value**, mrb_int*
f	Float	mrb_float*
i	Integer	mrb_int*
b	boolean	mrb_bool*
n	Symbol	mrb_sym*
&	block	mrb_value*

•     | rest (arguments, count)                     | ```mrb_value*```, ```int*```
  

Format specifiers after | are optional.

• ...: receiving arguments

Return value

number of parsed arguments (greater than or equal to 0)

Example

#include <mruby.h>
#include <mruby/compile.h>

static mrb_value
test_method(mrb_state *mrb, mrb_value self)
{
  mrb_value o;
  mrb_int i = 38250574;
  int n = mrb_get_args(mrb, "o|i", &o, &i);
  mrb_p(mrb, o);
  mrb_p(mrb, mrb_fixnum_value(i));
  mrb_p(mrb, mrb_fixnum_value(n));
  return mrb_nil_value();
}

int
main(void)
{
  const char code[] =
    "test('Second argument is optional. Print default value and number of parsed arguments: ')\n" \
    "test('Second argument is optional. Print 123 and number of parsed arguments:', 123)";
  mrb_state *mrb = mrb_open();
  mrb_define_method(mrb, mrb->kernel_module, "test", test_method, MRB_ARGS_ARG(1, 1));
  mrb_gc_arena_restore(mrb, 0);
  mrb_load_string(mrb, code);
  mrb_close(mrb);
  return 0;
}

Output:

"Second argument is optional. Print default value and parsed arguments: "
38250574
1
"Second argument is optional. Print 123 and parsed arguments:"
123
2

See also

• MRB_ARGS_REQ, MRB_ARGS_OPT, MRB_ARGS_ARG, MRB_ARGS_REST, MRB_ARGS_POST, MRB_ARGS_KEY, MRB_ARGS_BLOCK, MRB_ARGS_ANY, MRB_ARGS_NONE