method

count_symbols

v2_6_3 - Show latest stable - Class: ObjectSpace

count_symbols(*args)

public

Counts symbols for each Symbol type.

This method is only for MRI developers interested in performance and memory usage of Ruby programs.

If the optional argument, result_hash, is given, it is overwritten and returned. This is intended to avoid probe effect.

Note: The contents of the returned hash is implementation defined. It may be changed in future.

This method is only expected to work with C Ruby.

On this version of MRI, they have 3 types of Symbols (and 1 total counts).

* mortal_dynamic_symbol: GC target symbols (collected by GC)
* immortal_dynamic_symbol: Immortal symbols promoted from dynamic symbols (do not collected by GC)
* immortal_static_symbol: Immortal symbols (do not collected by GC)
* immortal_symbol: total immortal symbols (immortal_dynamic_symbol+immortal_static_symbol)

static VALUE
count_symbols(int argc, VALUE *argv, VALUE os)
{
    struct dynamic_symbol_counts dynamic_counts = {0, 0};
    VALUE hash = setup_hash(argc, argv);

    size_t immortal_symbols = rb_sym_immortal_count();
    rb_objspace_each_objects(cs_i, &dynamic_counts);

    rb_hash_aset(hash, ID2SYM(rb_intern("mortal_dynamic_symbol")),   SIZET2NUM(dynamic_counts.mortal));
    rb_hash_aset(hash, ID2SYM(rb_intern("immortal_dynamic_symbol")), SIZET2NUM(dynamic_counts.immortal));
    rb_hash_aset(hash, ID2SYM(rb_intern("immortal_static_symbol")),  SIZET2NUM(immortal_symbols - dynamic_counts.immortal));
    rb_hash_aset(hash, ID2SYM(rb_intern("immortal_symbol")),         SIZET2NUM(immortal_symbols));

    return hash;
}

count_symbols

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