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Diffstat (limited to 'system/doc/reference_manual/errors.xml')
| -rw-r--r-- | system/doc/reference_manual/errors.xml | 67 |
1 files changed, 37 insertions, 30 deletions
diff --git a/system/doc/reference_manual/errors.xml b/system/doc/reference_manual/errors.xml index dde6e68f4a..66ecf6aa94 100644 --- a/system/doc/reference_manual/errors.xml +++ b/system/doc/reference_manual/errors.xml @@ -4,7 +4,7 @@ <chapter> <header> <copyright> - <year>2003</year><year>2013</year> + <year>2003</year><year>2015</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -38,12 +38,12 @@ <item>Run-time errors</item> <item>Generated errors</item> </list> - <p>A compile-time error, for example a syntax error, should not + <p>A compile-time error, for example a syntax error, does not cause much trouble as it is caught by the compiler.</p> <p>A logical error is when a program does not behave as intended, - but does not crash. An example could be that nothing happens when + but does not crash. An example is that nothing happens when a button in a graphical user interface is clicked.</p> - <p>A run-time error is when a crash occurs. An example could be + <p>A run-time error is when a crash occurs. An example is when an operator is applied to arguments of the wrong type. The Erlang programming language has built-in features for handling of run-time errors.</p> @@ -54,23 +54,23 @@ of class <c>error</c>. </p> <p>A generated error is when the code itself calls - <c>exit/1</c> or <c>throw/1</c>. Note that emulated run-time + <c>exit/1</c> or <c>throw/1</c>. Notice that emulated run-time errors are not denoted as generated errors here. </p> <p>Generated errors are exceptions of classes <c>exit</c> and <c>throw</c>. </p> <p>When a run-time error or generated error occurs in Erlang, - execution for the process which evaluated + execution for the process that evaluated the erroneous expression is stopped. This is referred to as a <em>failure</em>, that execution or evaluation <em>fails</em>, or that the process <em>fails</em>, - <em>terminates</em> or <em>exits</em>. Note that a process may + <em>terminates</em>, or <em>exits</em>. Notice that a process can terminate/exit for other reasons than a failure.</p> - <p>A process that terminates will emit an <em>exit signal</em> with + <p>A process that terminates emits an <em>exit signal</em> with an <em>exit reason</em> that says something about which error - has occurred. Normally, some information about the error will - be printed to the terminal.</p> + has occurred. Normally, some information about the error is + printed to the terminal.</p> </section> <section> @@ -78,10 +78,12 @@ <p>Exceptions are run-time errors or generated errors and are of three different classes, with different origins. The <seealso marker="expressions#try">try</seealso> expression - (appeared in Erlang 5.4/OTP-R10B) + (new in Erlang 5.4/OTP R10B) can distinguish between the different classes, whereas the <seealso marker="expressions#catch">catch</seealso> - expression can not. They are described in the Expressions chapter.</p> + expression cannot. They are described in + <seealso marker="expressions">Expressions + </seealso>.</p> <table> <row> <cell align="left" valign="middle"><em>Class</em></cell> @@ -89,7 +91,9 @@ </row> <row> <cell align="left" valign="middle"><c>error</c></cell> - <cell align="left" valign="middle">Run-time error for example <c>1+a</c>, or the process called <c>erlang:error/1,2</c> (appeared in Erlang 5.4/OTP-R10B)</cell> + <cell align="left" valign="middle">Run-time error, + for example, <c>1+a</c>, or the process called + <c>erlang:error/1,2</c> (new in Erlang 5.4/OTP R10B)</cell> </row> <row> <cell align="left" valign="middle"><c>exit</c></cell> @@ -102,11 +106,11 @@ <tcaption>Exception Classes.</tcaption> </table> <p>An exception consists of its class, an exit reason - (the <seealso marker="#exit_reasons">Exit Reason</seealso>), - and a stack trace (that aids in finding the code location of + (see <seealso marker="#exit_reasons">Exit Reason</seealso>), + and a stack trace (which aids in finding the code location of the exception).</p> <p>The stack trace can be retrieved using - <c>erlang:get_stacktrace/0</c> (new in Erlang 5.4/OTP-R10B) + <c>erlang:get_stacktrace/0</c> (new in Erlang 5.4/OTP R10B) from within a <c>try</c> expression, and is returned for exceptions of class <c>error</c> from a <c>catch</c> expression.</p> <p>An exception of class <c>error</c> is also known as a run-time @@ -114,38 +118,38 @@ </section> <section> - <title>Handling of Run-Time Errors in Erlang</title> + <title>Handling of Run-time Errors in Erlang</title> <section> <title>Error Handling Within Processes</title> <p>It is possible to prevent run-time errors and other exceptions from causing the process to terminate by using <c>catch</c> or - <c>try</c>, see the Expressions chapter about - <seealso marker="expressions#catch">Catch</seealso> - and <seealso marker="expressions#try">Try</seealso>.</p> + <c>try</c>, see <seealso marker="expressions"> + Expressions</seealso> about + <seealso marker="expressions#catch">catch</seealso> + and <seealso marker="expressions#try">try</seealso>.</p> </section> <section> <title>Error Handling Between Processes</title> <p>Processes can monitor other processes and detect process terminations, see - the <seealso marker="processes#errors">Processes</seealso> - chapter.</p> + <seealso marker="processes#errors">Processes</seealso>.</p> </section> </section> <section> <marker id="exit_reasons"></marker> <title>Exit Reasons</title> - <p>When a run-time error occurs, - that is an exception of class <c>error</c>, - the exit reason is a tuple <c>{Reason,Stack}</c>. + <p>When a run-time error occurs, + that is an exception of class <c>error</c>. + The exit reason is a tuple <c>{Reason,Stack}</c>, where <c>Reason</c> is a term indicating the type of error:</p> <table> <row> <cell align="left" valign="middle"><em>Reason</em></cell> - <cell align="left" valign="middle"><em>Type of error</em></cell> + <cell align="left" valign="middle"><em>Type of Error</em></cell> </row> <row> <cell align="left" valign="middle"><c>badarg</c></cell> @@ -181,7 +185,7 @@ </row> <row> <cell align="left" valign="middle"><c>{badfun,F}</c></cell> - <cell align="left" valign="middle">There is something wrong with a fun <c>F</c>.</cell> + <cell align="left" valign="middle">Something is wrong with a fun <c>F</c>.</cell> </row> <row> <cell align="left" valign="middle"><c>{badarity,F}</c></cell> @@ -201,14 +205,17 @@ </row> <row> <cell align="left" valign="middle"><c>system_limit</c></cell> - <cell align="left" valign="middle">A system limit has been reached. See Efficiency Guide for information about system limits.</cell> + <cell align="left" valign="middle">A system limit has been reached. + See <seealso marker="doc/efficiency_guide:advanced"> + Efficiency Guide</seealso> for information about system limits. + </cell> </row> - <tcaption>Exit Reasons.</tcaption> + <tcaption>Exit Reasons</tcaption> </table> <p><c>Stack</c> is the stack of function calls being evaluated when the error occurred, given as a list of tuples <c>{Module,Name,Arity}</c> with the most recent function call - first. The most recent function call tuple may in some + first. The most recent function call tuple can in some cases be <c>{Module,Name,[Arg]}</c>.</p> </section> </chapter> |