diff options
| author | Lang Hames <lhames@gmail.com> | 2016-11-07 22:33:13 +0000 |
|---|---|---|
| committer | Lang Hames <lhames@gmail.com> | 2016-11-07 22:33:13 +0000 |
| commit | 19a2308afd2ae05170e21c7213b15f5b9ebdead3 (patch) | |
| tree | 85e2b24906ba1c0f1eaac37d49df74ae6fe42296 /llvm/docs/ProgrammersManual.rst | |
| parent | c784b36fca7bf7e415b4f05a83a49915ae766b7d (diff) | |
[docs] Add a pointer to ExitOnError to the discussion of handleErrors in the
programmer's manual.
ExitOnError is often a better alternative to handleErrors for tool code. This
patch makes it easier to find the ExitOnError discussion when reading the
handleErrors section.
Thanks to Peter Collingbourne for the suggestion.
llvm-svn: 286167
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 adf6fd62fc98..e4d3ddb7bd9d 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 """"""""""""""""""""""""""""""""""""""" |