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authorLukas Larsson <[email protected]>2016-03-17 16:02:16 +0100
committerLukas Larsson <[email protected]>2016-04-15 15:08:18 +0200
commit2a0e30cb155b80273eb43bc0e01376b68a5fb5b0 (patch)
tree884394c143476018db86526f09d2cf7b4305792a /lib/runtime_tools/doc/src
parenta1cde0f881ee4865d38e2e6e88cc71dcd362fdd2 (diff)
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runtime_tools: Lots of dbg docs updates
Diffstat (limited to 'lib/runtime_tools/doc/src')
-rw-r--r--lib/runtime_tools/doc/src/dbg.xml281
1 files changed, 165 insertions, 116 deletions
diff --git a/lib/runtime_tools/doc/src/dbg.xml b/lib/runtime_tools/doc/src/dbg.xml
index 0232cc0453..ccb3bca50e 100644
--- a/lib/runtime_tools/doc/src/dbg.xml
+++ b/lib/runtime_tools/doc/src/dbg.xml
@@ -36,14 +36,30 @@
<modulesummary>The Text Based Trace Facility</modulesummary>
<description>
<p>This module implements a text based interface to the
- <c>trace/3</c> and the <c>trace_pattern/2</c> BIFs. It makes it
- possible to trace functions, processes and messages on text based
- terminals. It can be used instead of, or as complement to, the
- <c>pman</c> module.
- </p>
- <p>For some examples of how to use <c>dbg</c> from the Erlang
+ <c><seealso marker="erts:erlang#trace-3">trace/3</seealso></c> and the
+ <c><seealso marker="erts:erlang#trace_pattern-2">trace_pattern/2</seealso></c> BIFs. It makes it
+ possible to trace functions, processes, ports and messages.
+ </p>
+ <p>
+ To quickly get started on tracing function calls you can use the following
+ code in the Erlang shell:
+ </p>
+ <pre>
+1> dbg:tracer(). %% Start the default trace message receiver
+{ok,&lt;0.36.0>}
+2> dbg:p(all, c). %% Setup call (c) tracing on all processes
+{ok,[{matched,nonode@nohost,26}]}
+3> dbg:tp(lists, seq, x). %% Setup an exception return trace (x) on lists:seq
+{ok,[{matched,nonode@nohost,2},{saved,x}]}
+4> lists:seq(1,10).
+(&lt;0.34.0>) call lists:seq(1,10)
+(&lt;0.34.0>) returned from lists:seq/2 -> [1,2,3,4,5,6,7,8,9,10]
+[1,2,3,4,5,6,7,8,9,10]
+ </pre>
+ <p>
+ For more examples of how to use <c>dbg</c> from the Erlang
shell, see the <seealso marker="#simple_example">simple example</seealso> section.
- </p>
+ </p>
<p>The utilities are also suitable to use in system testing on
large systems, where other tools have too much impact on the
system performance. Some primitive support for sequential tracing
@@ -164,53 +180,66 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<desc>
<p>Traces <c>Item</c> in accordance to the value specified
by <c>Flags</c>. The variation of <c>Item</c> is listed below:</p>
- <list type="bulleted">
- <item>If the <c>Item</c> is a <c>pid()</c>, the corresponding
- process is traced. The process may be a remote process
- (on another Erlang node). The node must be in the list of
- traced nodes (see <seealso marker="#n"><c>n/1</c></seealso> and
- <c>tracer/0/2/3</c>).</item>
- <item>If the <c>Item</c> is the atom <c>all</c>, all processes in the
- system as well as all processes created hereafter are
- to be traced. This also affects all nodes added with the
- <c>n/1</c> or <c>tracer/0/2/3</c> function.</item>
- <item>If the <c>Item</c> is the atom <c>new</c>, no currently existing
- processes are affected, but every process created after the
- call is.This also affects all nodes added with the
- <c>n/1</c> or <c>tracer/0/2/3</c> function.</item>
- <item>If the <c>Item</c> is the atom <c>existing</c>, all
- existing processes are traced, but new processes will not
- be affected.This also affects all nodes added with the
- <c>n/1</c> or <c>tracer/0/2/3</c> function.</item>
- <item>If the <c>Item</c> is an atom other than <c>all</c>,
- <c>new</c> or <c>existing</c>, the process with the
- corresponding registered name is traced.The process may be a
- remote process (on another Erlang node). The node must be added
- with the <c>n/1</c> or <c>tracer/0/2/3</c> function.</item>
- <item>If the <c>Item</c> is an integer, the process <c><![CDATA[<0.Item.0>]]></c> is
- traced.</item>
- <item>If the <c>Item</c> is a tuple <c>{X, Y, Z}</c>, the
- process <c><![CDATA[<X.Y.Z>]]></c> is
- traced. </item>
+ <taglist>
+ <tag><c>pid()</c> or <c>port()</c></tag>
+ <item>The corresponding process or port is traced. The process or port may
+ be a remote process or port (on another Erlang node). The node must
+ be in the list of traced nodes (see <seealso marker="#n-1"><c>n/1</c></seealso>
+ and <c><seealso marker="#tracer-3">tracer/3</seealso></c>).</item>
+ <tag><c>all</c></tag>
+ <item>All processes and ports in the system as well as all processes and ports
+ created hereafter are to be traced.</item>
+ <tag><c>all_processes</c></tag>
+ <item>All processes in the system as well as all processes created hereafter are to be traced.</item>
+ <tag><c>all_ports</c></tag>
+ <item>All ports in the system as well as all ports created hereafter are to be traced.</item>
+ <tag><c>new</c></tag>
+ <item>All processes and ports created after the call is are to be traced.</item>
+ <tag><c>new_processes</c></tag>
+ <item>All processes created after the call is are to be traced.</item>
+ <tag><c>new_ports</c></tag>
+ <item>All ports created after the call is are to be traced.</item>
+ <tag><c>existing</c></tag>
+ <item>All existing processes and ports are traced.</item>
+ <tag><c>existing_processes</c></tag>
+ <item>All existing processes are traced.</item>
+ <tag><c>existing_ports</c></tag>
+ <item>All existing ports are traced.</item>
+ <tag><c>atom()</c></tag>
+ <item>The process or port with the corresponding registered name is traced. The process or
+ port may be a remote process (on another Erlang node). The node must be
+ added with the <c><seealso marker="#n-1">n/1</seealso></c> or
+ <c><seealso marker="#tracer-3">tracer/3</seealso></c> function.</item>
+ <tag><c>integer()</c></tag>
+ <item>The process <c><![CDATA[<0.Item.0>]]></c> is traced.</item>
+ <tag><c>{X, Y, Z}</c></tag>
+ <item>The process <c><![CDATA[<X.Y.Z>]]></c> is traced. </item>
+ <tag><c>string()</c></tag>
<item>If the <c>Item</c> is a string <![CDATA["<X.Y.Z>"]]>
- as returned from <c>pid_to_list/1</c>, the process
+ as returned from <c><seealso marker="erts:erlang#pid_to_list-1">pid_to_list/1</seealso></c>, the process
<c><![CDATA[<X.Y.Z>]]></c> is traced. </item>
- </list>
+ </taglist>
+
+ <p>When enabling an <c>Item</c> that represents a group of processes,
+ the <c>Item</c> is enabled on all nodes added with the
+ <c><seealso marker="#n-1">n/1</seealso></c> or
+ <c><seealso marker="#tracer-3">tracer/3</seealso></c> function.</p>
+
<p><c>Flags</c> can be a single atom,
or a list of flags. The available flags are:
</p>
<taglist>
<tag><c>s (send)</c></tag>
<item>
- <p>Traces the messages the process sends.</p>
+ <p>Traces the messages the process or port sends.</p>
</item>
<tag><c>r (receive)</c></tag>
<item>
- <p>Traces the messages the process receives.</p>
+ <p>Traces the messages the process or port receives.</p>
</item>
<tag><c>m (messages)</c></tag>
<item>
- <p>Traces the messages the process receives and sends.</p>
+ <p>Traces the messages the process or port receives and sends.</p>
</item>
<tag><c>c (call)</c></tag>
<item>
@@ -221,6 +250,10 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<item>
<p>Traces process related events to the process.</p>
</item>
+ <tag><c>ports</c></tag>
+ <item>
+ <p>Traces port related events to the port.</p>
+ </item>
<tag><c>sos (set on spawn)</c></tag>
<item>
<p>Lets all processes created by the traced
@@ -241,8 +274,8 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<tag><c>sofl (set on first link)</c></tag>
<item>
<p>This is the same as <c>sol</c>, but only for
- the first call to
- <c>link/1</c> by the traced process.</p>
+ the first call to
+ <c><seealso marker="erts:erlang#link-1">link/1</seealso></c> by the traced process.</p>
</item>
<tag><c>all</c></tag>
<item>
@@ -258,7 +291,7 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<c>erlang:trace/3</c></p>
<p>The function returns either an error tuple or a tuple
<c>{ok, List}</c>. The <c>List</c> consists of
- specifications of how many processes that matched (in the
+ specifications of how many processes and ports that matched (in the
case of a pure pid() exactly 1). The specification of
matched processes is <c>{matched, Node, N}</c>. If the
remote processor call,<c>rpc</c>, to a remote node fails,
@@ -286,9 +319,9 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
</func>
<func>
<name>i() -> ok</name>
- <fsummary>Display information about all traced processes.</fsummary>
+ <fsummary>Display information about all traced processes and ports.</fsummary>
<desc>
- <p>Displays information about all traced processes.</p>
+ <p>Displays information about all traced processes and ports.</p>
</desc>
</func>
<func>
@@ -327,35 +360,41 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
</type>
<desc>
<p>This function enables call trace for one or more
- functions. All exported functions matching the <c>{Module, Function, Arity}</c> argument will be concerned, but the
+ functions. All exported functions matching the <c>{Module, Function, Arity}</c>
+ argument will be concerned, but the
<c>match_spec()</c> may further narrow down the set of function
calls generating trace messages.</p>
<p>For a description of the <c>match_spec()</c> syntax,
please turn to the
<em>User's guide</em> part of the online
documentation for the runtime system (<em>erts</em>). The
- chapter <em>Match Specification in Erlang</em> explains the
- general match specification "language".</p>
+ chapter <em><seealso marker="erts:match_spec">Match Specifications in Erlang</seealso></em>
+ explains the general match specification "language".
+ The most common generic match specifications used can be
+ found as <c>Built-inAlias</c>', see
+ <c><seealso marker="#ltp-0">ltp/0</seealso></c> below for details.
+ </p>
<p>The Module, Function and/or Arity parts of the tuple may
be specified as the atom <c>'_'</c> which is a "wild-card"
matching all modules/functions/arities. Note, if the
Module is specified as <c>'_'</c>, the Function and Arity
parts have to be specified as '_' too. The same holds for the
Functions relation to the Arity.</p>
- <p>All nodes added with <c>n/1</c> or <c>tracer/0/2/3</c> will
+ <p>All nodes added with <c><seealso marker="#n-1">n/1</seealso></c> or
+ <c><seealso marker="#tracer-3">tracer/3</seealso></c> will
be affected by this call, and if Module is not <c>'_'</c>
the module will be loaded on all nodes.</p>
<p>The function returns either an error tuple or a tuple
<c>{ok, List}</c>. The <c>List</c> consists of specifications of how
- many functions that matched, in the same way as the processes
- are presented in the return value of <c>p/2</c>. </p>
+ many functions that matched, in the same way as the processes and ports
+ are presented in the return value of <c><seealso marker="#p-2">p/2</seealso></c>. </p>
<p>There may be a tuple <c>{saved, N}</c> in the return value,
if the MatchSpec is other
than []. The integer <c>N</c> may then be used in
subsequent calls to this function and will stand as an
"alias" for the given expression. There are also a couple of
- built-in aliases for common expressions, see <c>ltp/0</c> below
- for details.</p>
+ built-in aliases for common expressions, see
+ <c><seealso marker="#ltp-0">ltp/0</seealso></c> below for details.</p>
<p>If an error is returned, it can be due to errors in
compilation of the match specification. Such errors are
presented as a list of tuples <c>{error, string()}</c> where
@@ -394,7 +433,7 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<name>tpl({Module, Function, Arity}, MatchSpec) -> {ok, MatchDesc} | {error, term()}</name>
<fsummary>Set pattern for traced local (as well as global) function calls</fsummary>
<desc>
- <p>This function works as <c>tp/2</c>, but enables
+ <p>This function works as <c><seealso marker="#tp-2">tp/2</seealso></c>, but enables
tracing for local calls (and local functions) as well as for
global calls (and functions).</p>
</desc>
@@ -441,10 +480,10 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<p>This function disables call tracing on the specified
functions. The semantics of the parameter is the same
as for the corresponding function specification in
- <c>tp/2</c> or <c>tpl/2</c>. Both local and global call trace
+ <c><seealso marker="#tp-2">tp/2</seealso></c> or <c><seealso marker="#tpl-2">tpl/2</seealso></c>. Both local and global call trace
is disabled. </p>
<p>The return value reflects how many functions that matched,
- and is constructed as described in <c>tp/2</c>. No tuple
+ and is constructed as described in <c><seealso marker="#tp-2">tp/2</seealso></c>. No tuple
<c>{saved, N}</c> is however ever returned (for obvious reasons).</p>
</desc>
</func>
@@ -480,8 +519,8 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<name>ctpl({Module, Function, Arity}) -> {ok, MatchDesc} | {error, term()}</name>
<fsummary>Clear call trace pattern for the specified functions</fsummary>
<desc>
- <p>This function works as <c>ctp/1</c>, but only disables
- tracing set up with <c>tpl/2</c> (not with <c>tp/2</c>).</p>
+ <p>This function works as <c><seealso marker="#ctp-1">ctp/1</seealso></c>, but only disables
+ tracing set up with <c><seealso marker="#tpl-2">tpl/2</seealso></c> (not with <c><seealso marker="#tp-2">tp/2</seealso></c>).</p>
</desc>
</func>
<func>
@@ -516,8 +555,8 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<name>ctpg({Module, Function, Arity}) -> {ok, MatchDesc} | {error, term()}</name>
<fsummary>Clear call trace pattern for the specified functions</fsummary>
<desc>
- <p>This function works as <c>ctp/1</c>, but only disables
- tracing set up with <c>tp/2</c> (not with <c>tpl/2</c>).</p>
+ <p>This function works as <c><seealso marker="#ctp-1">ctp/1</seealso></c>, but only disables
+ tracing set up with <c><seealso marker="#tp-2">tp/2</seealso></c> (not with <c><seealso marker="#tpl-2">tpl/2</seealso></c>).</p>
</desc>
</func>
<func>
@@ -526,13 +565,13 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<desc>
<p>Use this function to recall all match specifications previously
used in the session (i. e. previously saved during calls
- to <c>tp/2</c>, and built-in match specifications.
+ to <c><seealso marker="#tp-2">tp/2</seealso></c>, and built-in match specifications.
This is very useful, as a complicated
match_spec can be quite awkward to write. Note that the
- match specifications are lost if <c>stop/0</c> is called.</p>
+ match specifications are lost if <c><seealso marker="#stop-0">stop/0</seealso></c> is called.</p>
<p>Match specifications used can be saved in a file (if a
read-write file system is present) for use in later
- debugging sessions, see <c>wtp/1</c> and <c>rtp/1</c></p>
+ debugging sessions, see <c><seealso marker="#wtp-1">wtp/1</seealso></c> and <c><seealso marker="#rtp-1">rtp/1</seealso></c></p>
<p>There are three built-in trace patterns:
<c>exception_trace</c>, <c>caller_trace</c>
and <c>caller_exception_trace</c> (or <c>x</c>, <c>c</c> and
@@ -555,10 +594,10 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<fsummary>Delete all saved match specifications.</fsummary>
<desc>
<p>Use this function to "forget" all match specifications
- saved during calls to <c>tp/2</c>.
+ saved during calls to <c><seealso marker="#tp-2">tp/2</seealso></c>.
This is useful when one wants to restore other match
- specifications from a file with <c>rtp/1</c>. Use
- <c>dtp/1</c> to delete specific saved match specifications. </p>
+ specifications from a file with <c><seealso marker="#rtp-1">rtp/1</seealso></c>. Use
+ <c><seealso marker="#dtp-1">dtp/1</seealso></c> to delete specific saved match specifications. </p>
</desc>
</func>
<func>
@@ -569,7 +608,7 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
</type>
<desc>
<p>Use this function to "forget" a specific match specification
- saved during calls to <c>tp/2</c>.</p>
+ saved during calls to <c><seealso marker="#tp-2">tp/2</seealso></c>.</p>
</desc>
</func>
<func>
@@ -581,12 +620,12 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
</type>
<desc>
<p>This function will save all match specifications saved
- during the session (during calls to <c>tp/2</c>)
+ during the session (during calls to <c><seealso marker="#tp-2">tp/2</seealso></c>)
and built-in match specifications in a text
file with the name designated by <c>Name</c>. The format
of the file is textual, why it can be edited with an
ordinary text editor, and then restored with
- <c>rtp/1</c>. </p>
+ <c><seealso marker="#rtp-1">rtp/1</seealso></c>. </p>
<p>Each match spec in the file ends with a full stop
(<c>.</c>) and new (syntactically correct) match
specifications can be added to the file manually.</p>
@@ -604,7 +643,7 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
</type>
<desc>
<p>This function reads match specifications from a file
- (possibly) generated by the <c>wtp/1</c> function. It checks
+ (possibly) generated by the <c><seealso marker="#wtp-1">wtp/1</seealso></c> function. It checks
the syntax of all match specifications and verifies that
they are correct. The error handling principle is "all or
nothing", i. e. if some of the match specifications are
@@ -612,14 +651,14 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
saved match specifications for the running system. </p>
<p>The match specifications in the file are <em>merged</em>
with the current match specifications, so that no duplicates
- are generated. Use <c>ltp/0</c> to see what numbers were
+ are generated. Use <c><seealso marker="#ltp-0">ltp/0</seealso></c> to see what numbers were
assigned to the specifications from the file.</p>
<p>The function will return an error, either due to I/O
problems (like a non existing or non readable file) or due
to file format problems. The errors from a bad format file
are in a more or less textual format, which will give a hint
- to what's causing the problem. <marker id="n"></marker>
-</p>
+ to what's causing the problem.
+ </p>
</desc>
</func>
<func>
@@ -631,12 +670,12 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
</type>
<desc>
<p>The <c>dbg</c> server keeps a list of nodes where tracing
- should be performed. Whenever a <c>tp/2</c> call or a
- <c>p/2</c> call is made, it is executed for all nodes in this
- list including the local node (except for <c>p/2</c> with a
- specific <c>pid()</c> as first argument, in which case the
+ should be performed. Whenever a <c><seealso marker="#tp-2">tp/2</seealso></c> call or a
+ <c><seealso marker="#p-2">p/2</seealso></c> call is made, it is executed for all nodes in this
+ list including the local node (except for <c><seealso marker="#p-2">p/2</seealso></c> with a
+ specific <c>pid()</c> or <c>port()</c> as first argument, in which case the
command is executed only on the node where the designated
- process resides).
+ process or port resides).
</p>
<p>This function adds a remote node (<c>Nodename</c>) to the
list of nodes where tracing is performed. It starts a tracer
@@ -645,17 +684,17 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
distribution). If no tracer process is running on the local
node, the error reason <c>no_local_tracer</c> is returned. The
tracer process on the local node must be started with the
- <c>tracer/0/2</c> function.
+ <c><seealso marker="#tracer-2">tracer/0/2</seealso></c> function.
</p>
<p>If <c>Nodename</c> is the local node, the error reason
<c>cant_add_local_node</c> is returned.
</p>
- <p>If a trace port (see <seealso marker="#trace_port"><c>trace_port/2</c></seealso>) is
+ <p>If a trace port (see <seealso marker="#trace_port-2"><c>trace_port/2</c></seealso>) is
running on the local node, remote nodes can not be traced with
a tracer process. The error reason
<c>cant_trace_remote_pid_to_local_port</c> is returned. A
trace port can however be started on the remote node with the
- <c>tracer/3</c> function.
+ <c><seealso marker="#tracer-3">tracer/3</seealso></c> function.
</p>
<p>The function will also return an error if the node
<c>Nodename</c> is not reachable.</p>
@@ -669,7 +708,7 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
</type>
<desc>
<p>Clears a node from the list of traced nodes. Subsequent
- calls to <c>tp/2</c> and <c>p/2</c> will not consider that
+ calls to <c><seealso marker="#tp-2">tp/2</seealso></c> and <c><seealso marker="#p-2">p/2</seealso></c> will not consider that
node, but tracing already activated on the node will continue
to be in effect.</p>
<p>Returns <c>ok</c>, cannot fail.</p>
@@ -688,37 +727,42 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<desc>
<p>This function starts a server on the local node that will
be the recipient of all trace messages. All subsequent calls
- to <c>p/2</c> will result in messages sent to the newly
+ to <c><seealso marker="#p-2">p/2</seealso></c> will result in messages sent to the newly
started trace server.</p>
<p>A trace server started in this way will simply display the
trace messages in a formatted way in the Erlang shell
- (i. e. use io:format). See <c>tracer/2</c> for a description
- of how the trace message handler can be customized. <marker id="tracer2"></marker>
-</p>
- <p>To start a similar tracer on a remote node, use <c>n/1</c>.</p>
+ (i. e. use io:format). See <c><seealso marker="#tracer-2">tracer/2</seealso></c> for a description
+ of how the trace message handler can be customized.
+ </p>
+ <p>To start a similar tracer on a remote node, use <c><seealso marker="#n-1">n/1</seealso></c>.</p>
</desc>
</func>
<func>
<name>tracer(Type, Data) -> {ok, pid()} | {error, Error}</name>
<fsummary>Start a tracer server with additional parameters</fsummary>
<type>
- <v>Type = port | process</v>
- <v>Data = PortGenerator | HandlerSpec</v>
- <v>HandlerSpec = {HandlerFun, InitialData}</v>
- <v>HandlerFun = fun() (two arguments)</v>
- <v>InitialData = term()</v>
+ <v>Type = port | process | module</v>
+ <v>Data = PortGenerator | HandlerSpec | ModuleSpec</v>
<v>PortGenerator = fun() (no arguments)</v>
<v>Error = term()</v>
+ <v>HandlerSpec = {HandlerFun, InitialData}</v>
+ <v>HandlerFun = fun() (two arguments)</v>
+ <v>ModuleSpec = {TracerModule, TracerState}</v>
+ <v>ModuleModule = atom()</v>
+ <v>InitialData = TracerState = term()</v>
</type>
<desc>
<p>This function starts a tracer server with additional
parameters on the local node. The first parameter, the
<c>Type</c>, indicates if trace messages should be handled
- by a receiving process (<c>process</c>) or by a tracer port
- (<c>port</c>). For a description about tracer ports see
- <c>trace_port/2</c>.
+ by a receiving process (<c>process</c>), by a tracer port
+ (<c>port</c>) or by a tracer module
+ (<c>module</c>). For a description about tracer ports see
+ <c><seealso marker="#trace_port-2">trace_port/2</seealso></c>
+ and for a tracer modules see
+ <c><seealso marker="erts:erl_tracer">erl_tracer</seealso>.</c>
</p>
- <p>If <c>Type</c> is a process, a message handler function can
+ <p>If <c>Type</c> is <c>process</c>, a message handler function can
be specified (<c>HandlerSpec</c>). The handler function, which
should be a <c>fun</c> taking two arguments, will be called
for each trace message, with the first argument containing the
@@ -729,18 +773,22 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
choose any appropriate action to take when invoked, and can
save a state for the next invocation by returning it.
</p>
- <p>If <c>Type</c> is a port, then the second parameter should
+ <p>If <c>Type</c> is <c>port</c>, then the second parameter should
be a <em>fun</em> which takes no arguments and returns a
newly opened trace port when called. Such a <em>fun</em> is
- preferably generated by calling <c>trace_port/2</c>.
+ preferably generated by calling <c><seealso marker="#trace_port-2">trace_port/2</seealso></c>.
</p>
+ <p>if <c>Type</c> is <c>module</c>, then the second parameter should
+ be a tuple describing the <c><seealso marker="erts:erl_tracer">erl_tracer</seealso></c>
+ module to be used for tracing and the state to be used for
+ that tracer module.</p>
<p>If an error is returned, it can either be due to a tracer
server already running (<c>{error,already_started}</c>) or
due to the <c>HandlerFun</c> throwing an exception.
</p>
<p>To start a similar tracer on a remote node, use
- <c>tracer/3</c>. <marker id="trace_port"></marker>
-</p>
+ <c><seealso marker="#tracer-3">tracer/3</seealso></c>.
+ </p>
</desc>
</func>
<func>
@@ -750,20 +798,20 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<v>Nodename = atom()</v>
</type>
<desc>
- <p>This function is equivalent to <c>tracer/2</c>, but acts on
+ <p>This function is equivalent to <c><seealso marker="#tracer-2">tracer/2</seealso></c>, but acts on
the given node. A tracer is started on the node
(<c>Nodename</c>) and the node is added to the list of traced
nodes.
</p>
<note>
- <p>This function is not equivalent to <c>n/1</c>. While
- <c>n/1</c> starts a process tracer which redirects all trace
+ <p>This function is not equivalent to <c><seealso marker="#n-1">n/1</seealso></c>. While
+ <c><seealso marker="#n-1">n/1</seealso></c> starts a process tracer which redirects all trace
information to a process tracer on the local node (i.e. the
- trace control node), <c>tracer/3</c> starts a tracer of any
+ trace control node), <c><seealso marker="#tracer-3">tracer/3</seealso></c> starts a tracer of any
type which is independent of the tracer on the trace control
node.</p>
</note>
- <p>For details, see <seealso marker="#tracer2"><c>tracer/2</c></seealso>.</p>
+ <p>For details, see <c><seealso marker="#tracer-2">tracer/2</seealso></c>.</p>
</desc>
</func>
<func>
@@ -795,9 +843,9 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<c>file</c> and the <c>ip</c> trace drivers. The file driver
sends all trace messages into one or several binary files,
from where they later can be fetched and processed with the
- <c>trace_client/2</c> function. The ip driver opens a TCP/IP
+ <c><seealso marker="#trace_client-2">trace_client/2</seealso></c> function. The ip driver opens a TCP/IP
port where it listens for connections. When a client
- (preferably started by calling <c>trace_client/2</c> on
+ (preferably started by calling <c><seealso marker="#trace_client-2">trace_client/2</seealso></c> on
another Erlang node) connects, all trace messages are sent
over the IP network for further processing by the remote
client. </p>
@@ -836,7 +884,7 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
as fast as they are produced by the runtime system, a special
message is sent, which indicates how many messages that are
dropped. That message will arrive at the handler function
- specified in <c>trace_client/3</c> as the tuple <c>{drop, N}</c> where <c>N</c> is the number of consecutive messages
+ specified in <c><seealso marker="#trace_client-3">trace_client/3</seealso></c> as the tuple <c>{drop, N}</c> where <c>N</c> is the number of consecutive messages
dropped. In case of heavy tracing, drop's are likely to occur,
and they surely occur if no client is reading the trace
messages.</p>
@@ -890,7 +938,7 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
</item>
<tag><c>get_listen_port</c></tag>
<item>
- <p>Returns <c>{ok, IpPort}</c> where <c>IpPort</c>is
+ <p>Returns <c>{ok, IpPort}</c> where <c>IpPort</c> is
the IP port number used by the driver listen socket.
Only the ip trace driver supports this operation.</p>
</item>
@@ -913,7 +961,7 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<desc>
<p>This function starts a trace client that reads the output
created by a trace port driver and handles it in mostly the
- same way as a tracer process created by the <c>tracer/0</c>
+ same way as a tracer process created by the <c><seealso marker="#tracer-0">tracer/0</seealso></c>
function.</p>
<p>If <c>Type</c> is <c>file</c>, the client reads all trace
messages stored in the file named <c>Filename</c> or
@@ -925,7 +973,7 @@ Error: fun containing local erlang function calls ('is_atomm' called in guard)\
<p>If <c>Type</c> is <c>follow_file</c>, the client behaves as
in the <c>file</c> case, but keeps trying to read (and
process) more data
- from the file until stopped by <c>stop_trace_client/1</c>.
+ from the file until stopped by <c><seealso marker="#stop_trace_client-1">stop_trace_client/1</seealso></c>.
<c>WrapFilesSpec</c> is not allowed as second argument
for this <c>Type</c>.</p>
<p>If <c>Type</c> is <c>ip</c>, the client connects to the
@@ -981,10 +1029,10 @@ hello</pre>
<v>InitialData = term()</v>
</type>
<desc>
- <p>This function works exactly as <c>trace_client/2</c>, but
+ <p>This function works exactly as <c><seealso marker="#trace_client-2">trace_client/2</seealso></c>, but
allows you to write your own handler function. The handler
function works mostly as the one described in
- <c>tracer/2</c>, but will also have to be prepared to handle
+ <c><seealso marker="#tracer-2">tracer/2</seealso></c>, but will also have to be prepared to handle
trace messages of the form <c>{drop, N}</c>, where <c>N</c> is
the number of dropped messages. This pseudo trace message will
only occur if the ip trace driver is used.</p>
@@ -1003,7 +1051,7 @@ hello</pre>
<desc>
<p>This function shuts down a previously started trace
client. The <c>Pid</c> argument is the process id returned
- from the <c>trace_client/2</c> or <c>trace_client/3</c> call.</p>
+ from the <c><seealso marker="#trace_client-2">trace_client/2</seealso></c> or <c><seealso marker="#trace_client-3">trace_client/3</seealso></c> call.</p>
</desc>
</func>
<func>
@@ -1156,8 +1204,9 @@ SeqTrace [0]: (&lt;0.30.0>) &lt;0.25.0> ! {dbg,{ok,&lt;0.31.0>}} [Serial: {4,5}]
of causing a deadlock. This will happen if a group leader process generates a trace
message and the tracer process, by calling the trace handler function, sends an IO
request to the same group leader. The problem can only occur if the trace handler
- prints to tty using an <c>io</c> function such as <c>format/2</c>. Note that when
- <c>dbg:p(all,call)</c> is called, IO processes are also traced.
+ prints to tty using an <c>io</c> function such as <c><seealso marker="stdlib:io#format-2">format/2</seealso></c>.
+ Note that when
+ <c>dbg:p(all,call)</c> is called, IO processes are also traced.
Here's an example:</p>
<pre>
%% Using a default line editing shell