...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
BOOST_SCOPE_EXIT_ID — This macro allows to expand multiple scope exit declarations on the same line.
// In header: <boost/scope_exit.hpp>
BOOST_SCOPE_EXIT_ID(id, capture_list)
This macro is equivalent to BOOST_SCOPE_EXIT
but it can be expanded multiple times on the same line if different identifiers id
are provided for each expansion (see BOOST_SCOPE_EXIT
for more information).
Parameters:
id |
A unique identifier token which can be concatenated by the preprocessor (__LINE__ , scope_exit_number_1_on_line_123 , a combination of alphanumeric tokens, etc). |
capture_list |
Same as the capture_list parameter of the BOOST_SCOPE_EXIT macro. |
Note: This macro can be useful when the scope exit macros are expanded within user-defined macros (because nested macros expand on the same line). On some compilers (e.g., MSVC which supports the non standard __COUNTER__
macro) it might not be necessary to use this macro but the use of this macro is always necessary to ensure portability when expanding multiple scope exit declarations on the same line.
See: Tutorial section, BOOST_SCOPE_EXIT
, BOOST_SCOPE_EXIT_END_ID
, BOOST_SCOPE_EXIT_ALL_ID
, BOOST_SCOPE_EXIT_ID_TPL
.