Since we should generate `t=(sec+usec)` from a floating point number
`sec` should be `floor(f)` especially for negative numbers, if the place
for `usec` is specified. In contrast, we can `round` the below point
digits if we are going to ignore them. But we now use `round` instead of
`llround` which directly convert `double` to `long long`, to add
boundary check for conversion.
Previously, for example, it was possible to retrieve the `String` class as follows:
```console
% bin/mruby -e 'p Comparable::Enumerable::Errno::GC::Kernel::Math::ObjectSpace::String'
String
```
Note that this patch affects the API function `mrb_const_get()`.
The `REnv` object is difficult to deal with, and it would be ideal if the user did not have to manipulate it directly.
In some previous situations, it was necessary to call `mrb_env_unshare()`, a non-API function, after `mrb_load_string()` or similar.
With this patch, it is no longer necessary for users to use `mrb_env_unshare()` directly, as it is now handled internally simply by using the `mrb_vm_ci_env_clear()` function.
Also, `mrb_vm_ci_env_set()` is demoted from the `MRB_API` function for the same reason.
ref. commit 1ab3da6f08
As a Ruby convention, a method should return nil (not false) for the
exceptional value, e.g. String#index. File#_mtime should follow the
convention too.
```
mruby % doxygen -u
warning: Tag 'CLANG_ASSISTED_PARSING' at line 50 of file 'Doxyfile' belongs to an option that was not enabled at compile time.
This tag has been removed.
warning: Tag 'CLANG_OPTIONS' at line 51 of file 'Doxyfile' belongs to an option that was not enabled at compile time.
This tag has been removed.
warning: Tag 'TCL_SUBST' at line 238 of file 'Doxyfile' has become obsolete.
This tag has been removed.
warning: Tag 'COLS_IN_ALPHA_INDEX' at line 1075 of file 'Doxyfile' has become obsolete.
This tag has been removed.
warning: Tag 'FORMULA_TRANSPARENT' at line 1481 of file 'Doxyfile' has become obsolete.
This tag has been removed.
warning: Tag 'LATEX_SOURCE_CODE' at line 1769 of file 'Doxyfile' has become obsolete.
This tag has been removed.
warning: Tag 'RTF_SOURCE_CODE' at line 1851 of file 'Doxyfile' has become obsolete.
This tag has been removed.
warning: Tag 'DOCBOOK_PROGRAMLISTING' at line 1949 of file 'Doxyfile' has become obsolete.
This tag has been removed.
warning: Tag 'PERL_PATH' at line 2094 of file 'Doxyfile' has become obsolete.
This tag has been removed.
warning: Tag 'CLASS_DIAGRAMS' at line 2107 of file 'Doxyfile' has become obsolete.
This tag has been removed.
warning: Tag 'MSCGEN_PATH' at line 2116 of file 'Doxyfile' has become obsolete.
This tag has been removed.
warning: Tag 'DOT_FONTNAME' at line 2158 of file 'Doxyfile' has become obsolete.
This tag has been removed.
warning: Tag 'DOT_FONTSIZE' at line 2165 of file 'Doxyfile' has become obsolete.
This tag has been removed.
warning: Tag 'DOT_TRANSPARENT' at line 2391 of file 'Doxyfile' has become obsolete.
This tag has been removed.
Configuration file 'Doxyfile' updated.
```
Yukihiro "Matz" Matsumoto