diff options
Diffstat (limited to 'lib/kernel/doc/src/error_handler.xml')
| -rw-r--r-- | lib/kernel/doc/src/error_handler.xml | 53 |
1 files changed, 43 insertions, 10 deletions
diff --git a/lib/kernel/doc/src/error_handler.xml b/lib/kernel/doc/src/error_handler.xml index acbf9a2c6e..84ec3927c8 100644 --- a/lib/kernel/doc/src/error_handler.xml +++ b/lib/kernel/doc/src/error_handler.xml @@ -5,7 +5,7 @@ <header> <copyright> <year>1996</year> - <year>2011</year> + <year>2013</year> <holder>Ericsson AB, All Rights Reserved</holder> </copyright> <legalnotice> @@ -43,19 +43,52 @@ A (possibly empty) list of arguments <c>Arg1,..,ArgN</c> </type_desc> <desc> - <p>This function is evaluated if a call is made to + <p>This function is called by the run-time system if a call is made to <c><anno>Module</anno>:<anno>Function</anno>(Arg1,.., ArgN)</c> and <c><anno>Module</anno>:<anno>Function</anno>/N</c> is undefined. Note that <c>undefined_function/3</c> is evaluated inside the process making the original call.</p> - <p>If <c><anno>Module</anno></c> is interpreted, the interpreter is invoked - and the return value of the interpreted - <c><anno>Function</anno>(Arg1,.., ArgN)</c> call is returned.</p> - <p>Otherwise, it returns, if possible, the value of - <c>apply(<anno>Module</anno>, <anno>Function</anno>, <anno>Args</anno>)</c> after an attempt has been - made to autoload <c><anno>Module</anno></c>. If this is not possible, the - call to <c><anno>Module</anno>:<anno>Function</anno>(Arg1,.., ArgN)</c> fails with - exit reason <c>undef</c>.</p> + + <p>This function will first attempt to autoload + <c><anno>Module</anno></c>. If that is not possible, + an <c>undef</c> exception will be raised.</p> + + <p>If it was possible to load <c><anno>Module</anno></c> + and the function <c><anno>Function</anno>/N</c> is exported, + it will be called.</p> + + <p>Otherwise, if the function <c>'$handle_undefined_function'/2</c> + is exported, it will be called as + <c>'$handle_undefined_function'(</c><anno>Function</anno>, + <anno>Args</anno>). + </p> + <warning> + <p>Defining <c>'$handle_undefined_function'/2</c> in + ordinary application code is highly discouraged. It is very + easy to make subtle errors that can take a long time to + debug. Furthermore, none of the tools for static code + analysis (such as Dialyzer and Xref) supports the use of + <c>'$handle_undefined_function'/2</c> and no such support + will be added. Only use this function after having carefully + considered other, less dangerous, solutions. One example of + potential legitimate use is creating stubs for other + sub-systems during testing and debugging. + </p> + </warning> + <p>Otherwise an <c>undef</c> exception will be raised.</p> + </desc> + </func> + <func> + <name name="raise_undef_exception" arity="3"/> + <fsummary>Raise an undef exception</fsummary> + <type_desc variable="Args"> + A (possibly empty) list of arguments <c>Arg1,..,ArgN</c> + </type_desc> + <desc> + <p>Raise an <c>undef</c> exception with a stacktrace indicating + that <c><anno>Module</anno>:<anno>Function</anno>/N</c> is + undefined. + </p> </desc> </func> <func> |