It potentially breaks, for example, in the case of `mrb_int` is 64-bit
and more smaller type is passed by `%d`. In fact, the problem could
become apparent when I used `%d` to `backtrace_location::lineno` in
`src/backtrace.c:mrb_unpack_backtrace()` on AppVeyor.
Therefore, change `%d` for `int` (not `mrb_int`) so that it can be
used mostly without casting.
Format sequence syntax:
%[modifier]specifier
Modifiers:
----------+------------------------------------------------------------
Modifier | Meaning
----------+------------------------------------------------------------
! | Convert to string by corresponding `inspect` instead of
| corresponding `to_s`.
----------+------------------------------------------------------------
Specifiers:
----------+----------------+--------------------------------------------
Specifier | Argument Type | Note
----------+----------------+--------------------------------------------
c | char |
d,i | mrb_int |
f | mrb_float |
l | char*, mrb_int | Arguments are string and length.
n | mrb_sym |
s | char* | Argument is NUL terminated string.
t | mrb_value | Convert to type (class) of object.
v,S | mrb_value |
C | struct RClass* |
T | mrb_value | Convert to real type (class) of object.
Y | mrb_value | Same as `!v` if argument is `true`, `false`
| | or `nil`, otherwise same as `T`.
% | - | Convert to percent sign itself (no argument
| | taken).
----------+----------------+--------------------------------------------
This change will increase the binary size, but replacing all format strings
with new specifiers/modifiers will decrease the size because it reduces
inline expansion of `mrb_obj_value()`, etc. at the caller.
KOBAYASHI Shuji