diff options
Diffstat (limited to 'llvm/docs/ProgrammersManual.rst')
| -rw-r--r-- | llvm/docs/ProgrammersManual.rst | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/llvm/docs/ProgrammersManual.rst b/llvm/docs/ProgrammersManual.rst index adf6fd62fc9..e4d3ddb7bd9 100644 --- a/llvm/docs/ProgrammersManual.rst +++ b/llvm/docs/ProgrammersManual.rst @@ -469,8 +469,8 @@ a variadic list of "handlers", each of which must be a callable type (a function, lambda, or class with a call operator) with one argument. The ``handleErrors`` function will visit each handler in the sequence and check its argument type against the dynamic type of the error, running the first handler -that matches. This is the same process that is used for catch clauses in C++ -exceptions. +that matches. This is the same decision process that is used decide which catch +clause to run for a C++ exception. Since the list of handlers passed to ``handleErrors`` may not cover every error type that can occur, the ``handleErrors`` function also returns an Error value @@ -500,6 +500,11 @@ elsewhere in the program can easily turn a formerly exhaustive list of errors into a non-exhaustive list, risking unexpected program termination. Where possible, use handleErrors and propagate unknown errors up the stack instead. +For tool code, where errors can be handled by printing an error message then +exiting with an error code, the :ref:`ExitOnError <err_exitonerr>` utility +may be a better choice than handleErrors, as it simplifies control flow when +calling fallible functions. + StringError """"""""""" @@ -580,6 +585,8 @@ actually recognises three different forms of handler signature: Any error returned from a handler will be returned from the ``handleErrors`` function so that it can be handled itself, or propagated up the stack. +.. _err_exitonerr: + Using ExitOnError to simplify tool code """"""""""""""""""""""""""""""""""""""" |
