mruby configuration macros.

How to use these macros.

You can use mrbconfs with following ways:

• Write them in mrbconf.h.
• Using compiler flags is preferred when building a cross binaries or multiple mruby binaries since it's easier to use different mrbconf per each MRuby::Build.
• Most flags can be enabled by just commenting in.
• Pass them as compiler flags.
• Make sure you pass the same flags to all compilers since some mrbconf(e.g., MRB_GC_FIXED_ARENA) changes struct layout and cause memory access error when C and other language(e.g., C++) is mixed.

stdio setting.

MRB_DISABLE_STDIO

• When defined <stdio.h> functions won't be used.
• Some features will be disabled when this is enabled:
  • mrb_irep load/dump from/to file.
  • Compiling mruby script from file.
  • Printing features in src/print.c.

Debug macros.

MRB_ENABLE_DEBUG_HOOK

• When defined code fetch hook and debug OP hook will be enabled.
• When using any of the hook set function pointer code_fetch_hook and/or debug_op_hook of mrb_state.
• Fetch hook will be called before any OP.
• Debug OP hook will be called when dispatching OP_DEBUG.

MRB_DEBUG

• When defined mrb_assert* macro will be defined with macros from <assert.h>.
• Could be enabled via enable_debug method of MRuby::Build.

Stack configuration

MRB_STACK_EXTEND_DOUBLING

• If defined doubles the stack size when extending it.
• Else extends stack with MRB_STACK_GROWTH.

MRB_STACK_GROWTH

• Default value is 128.
• Used in stack extending.
• Ignored when MRB_STACK_EXTEND_DOUBLING is defined.

MRB_STACK_MAX

• Default value is 0x40000 - MRB_STACK_GROWTH.
• Raises RuntimeError when stack size exceeds this value.

Primitive type configuration.

MRB_USE_FLOAT

• When defined single precision floating point type(C type float) is used as mrb_float.
• Else double precision floating point type(C type double) is used as mrb_float.

MRB_INT16

• When defined int16_t will be defined as mrb_int.
• Conflicts with MRB_INT64.

MRB_INT64

• When defined int64_t will be defined as mrb_int.
• Conflicts with MRB_INT16.
• When MRB_INT16 or MRB_INT64 isn't defined int(most of the times 32-bit integer) will be defined as mrb_int.

Garbage collector configuration.

MRB_GC_STRESS

• When defined full GC is emitted per each RBasic allocation.
• Mainly used in memory manager debugging.

MRB_GC_TURN_OFF_GENERATIONAL

• When defined turns generational GC by default.

MRB_GC_FIXED_ARENA

• When defined used fixed size GC arena.
• Raises RuntimeError when this is defined and GC arena size exceeds MRB_GC_ARENA_SIZE.
• Useful tracking unnecessary mruby object allocation.

MRB_GC_ARENA_SIZE

• Default value is 100.
• Ignored when MRB_GC_FIXED_ARENA isn't defined.
• Defines fixed GC arena size.

MRB_HEAP_PAGE_SIZE

• Defines value is 1024.
• Specifies number of RBasic per each heap page.

Memory pool configuration.

POOL_ALIGNMENT

• Default value is 4.
• If you're allocating data types that requires alignment more than default value define the largest value of required alignment.

POOL_PAGE_SIZE

• Default value is 16000.
• Specifies page size of pool page.
• Smaller the value is increases memory overhead.

State atexit configuration.

MRB_FIXED_STATE_ATEXIT_STACK

• If defined enables fixed size mrb_state atexit stack.
• Raises RuntimeError when mrb_state_atexit call count to same mrb_state exceeds MRB_FIXED_STATE_ATEXIT_STACK_SIZE's value.

MRB_FIXED_STATE_ATEXIT_STACK_SIZE

• Default value is 5.
• If MRB_FIXED_STATE_ATEXIT_STACK isn't defined this macro is ignored.

mrb_value configuration.

MRB_ENDIAN_BIG

• If defined compiles mruby for big endian machines.
• Used in MRB_NAN_BOXING.
• Some mrbgem use this mrbconf.

MRB_NAN_BOXING

• If defined represent mrb_value in boxed double.
• Conflicts with MRB_USE_FLOAT.

MRB_WORD_BOXING

• If defined represent mrb_value as a word.
• If defined Float will be a mruby object with RBasic.

Instance variable configuration.

MRB_IV_SEGMENT_SIZE

• Default value is 4.
• Specifies size of each segment in segment list.

Other configuration.

MRB_UTF8_STRING

• Adds UTF-8 encoding support to character-oriented String instance methods.
• If it isn't defined, they only support the US-ASCII encoding.

MRB_FUNCALL_ARGC_MAX

• Default value is 16.
• Specifies 4th argument(argc) max value of mrb_funcall.
• Raises ArgumentError when the argc argument is bigger then this value mrb_funcall.

KHASH_DEFAULT_SIZE

• Default value is 32.
• Specifies default size of khash table bucket.
• Used in kh_init_ ## name function.

MRB_STR_BUF_MIN_SIZE

• Default value is 128.
• Specifies initial capacity of RString created by mrb_str_buf_new function..