-Here, two event rules are created. The first one has a single condition:
-the tracepoint name must match `hello:world`. The second one has two
-conditions:
-
-* The tracepoint name must match `hello:world`, _and_
-* The tracepoint's defined log level must be at least as severe as
- the `TRACE_INFO` level.
-
-In this case, the second event rule is pointless because the first one
-is more general: it does not care about the tracepoint's log level.
-If an event source matching both event rules is reached by the
-application's execution, only one event is emitted.
-
-The available conditions for the Linux kernel domain are:
-
-* Tracepoint/system call name ('EVENT' argument with
- option:--tracepoint or option:--syscall options) or
- dynamic probe/function name/address
- (option:--probe or option:--function option's argument) which must
- match event source's equivalent.
-+
-You can use `*` characters at any place in the tracepoint or system
-call name as wildcards to match zero or more characters. To use a
-literal `*` character, use :escwc:.
-
-* Filter expression (option:--filter option) executed against the
- dynamic values of event fields at execution time that must evaluate
- to true. See the <<filter-expr,Filter expression>> section
- below for more information.
-
-The available conditions for the application domains are:
-
-* Tracepoint name ('EVENT' with option:--tracepoint option) which must
- match event source's equivalent.
-+
-You can use `*` characters at any place in the tracepoint name as
-wildcards to match zero or more characters. To use a literal `*`
-character, use :escwc:. When you create an event rule with a tracepoint
-name containing a wildcard, you can exclude specific tracepoint names
-from the match with the option:--exclude option.
-
-* Filter expression (option:--filter option) executed against the
- dynamic values of event fields at execution time that must evaluate
- to true. See the <<filter-expr,Filter expression>> section
- below for more information.
-* Event's log level that must be at least as severe as a given
- log level (option:--loglevel option) or match exactly a given log
- level (option:--loglevel-only option).
-
-When using `lttng enable-event` with a set of conditions that does not
-currently exist for the chosen tracing session, domain, and channel,
-a new event rule is created. Otherwise, the existing event rule is
-enabled if it is currently disabled
-(see man:lttng-disable-event(1)).
-
-The option:--all option can be used alongside the option:--tracepoint
-or option:--syscall options. When this option is used, no 'EVENT'
-argument must be specified. This option defines a single event rule
-matching _all_ the possible events of a given tracing domain for the
-chosen channel and tracing session. It is the equivalent of an 'EVENT'
-argument named `*` (wildcard).
-
-
-[[filter-expr]]
-Filter expression
-~~~~~~~~~~~~~~~~~
-A filter expression can be specified with the option:--filter option
-when creating a new event rule. If the filter expression evaluates
-to true when executed against the dynamic values of an event's fields
-when tracing, the filtering condition passes.
+* The process for which LTTng creates{nbsp}__E__ to match is allowed to
+ record events.
++
+All processes are allowed to record events on tracing session
+creation.
++
+Use the man:lttng-track(1) and man:lttng-untrack(1) commands to select
+which processes are allowed to record events based on specific process
+attributes.
+--
+
+The dedicated command-line options of most conditions are optional: if
+you don't specify the option, the associated condition is always
+satisfied.
+
+
+[[inst-point-type-cond]]
+Instrumentation point type condition
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+An event{nbsp}__E__ satisfies the instrumentation point type condition
+of a recording event rule if the instrumentation point from which LTTng
+creates{nbsp}__E__ is:
+
+For the Linux kernel tracing domain (option:--kernel option)::
+ With the option:--tracepoint option or without any other instrumentation point type option:::
+ An LTTng kernel tracepoint, that is, a statically defined point
+ in the source code of the kernel image or of a kernel module
+ with LTTng kernel tracer macros.
++
+As of LTTng{nbsp}{lttng_version}, this is the default instrumentation
+point type of the Linux kernel tracing domain, but this may change in
+the future.
++
+List the available Linux kernel tracepoints with `lttng list --kernel`.
+See man:lttng-list(1) to learn more.
+
+ With the option:--syscall option:::
+ The entry and exit of a Linux kernel system call.
++
+List the available Linux kernel system call instrumentation points with
+`lttng list --kernel --syscall`. See man:lttng-list(1) to learn more.
+
+ With the option:--probe option:::
+ A Linux kprobe, that is, a single probe dynamically placed in
+ the compiled kernel code.
++
+The argument of the option:--probe option is the location of the
+kprobe to insert, either a symbol or a
+memory address, while 'RECORDNAME' is the name of the record
+of{nbsp}__E__ (see the <<er-name,Event record name>> section below).
++
+The payload of a Linux kprobe event is empty.
+
+ With the option:--userspace-probe option:::
+ A Linux user space probe, that is, a single probe dynamically
+ placed at the entry of a compiled user space application/library
+ function through the kernel.
++
+The argument of the option:--userspace-probe option is the location
+of the user space probe to insert, one of:
++
+--
+* A path and symbol (ELF method).
+* A path, provider name, and probe name (SystemTap User-level Statically
+ Defined Tracing (USDT) method; a DTrace-style marker).
++
+As of LTTng{nbsp}{lttng_version}, LTTng only supports USDT probes which
+are :not: reference-counted.
+--
++
+'RECORDNAME' is the name of the record of{nbsp}__E__ (see the
+<<er-name,Event record name>> section below).
++
+The payload of a Linux user space probe event is empty.
+
+ With the option:--function option:::
+ A Linux kretprobe, that is, two probes dynamically placed at the
+ entry and exit of a function in the compiled kernel code.
++
+The argument of the option:--function option is the location of the
+Linux kretprobe to insert, either a symbol or
+a memory address, while 'RECORDNAME' is the name of the record
+of{nbsp}__E__ (see the <<er-name,Event record name>> section below).
++
+The payload of a Linux kretprobe event is empty.
+
+For the user space tracing domain (option:--userspace option)::
+ With or without the option:--tracepoint option:::
+ An LTTng user space tracepoint, that is, a statically defined
+ point in the source code of a C/$$C++$$ application/library with
+ LTTng user space tracer macros.
++
+As of LTTng{nbsp}{lttng_version}, this is the default and sole
+instrumentation point type of the user space tracing domain, but this
+may change in the future.
++
+List the available user space tracepoints with `lttng list --userspace`.
+See man:lttng-list(1) to learn more.
+
+For the `java.util.logging` (option:--jul option), Apache log4j (option:--log4j option), and Python (option:--python option) tracing domains::
+ With or without the option:--tracepoint option:::
+ A logging statement.
++
+As of LTTng{nbsp}{lttng_version}, this is the default and sole
+instrumentation point type of the `java.util.logging`, Apache log4j, and
+Python tracing domains, but this may change in the future.
++
+List the available Java and Python loggers with `lttng list --jul`,
+`lttng list --log4j`, and `lttng list --python`. See man:lttng-list(1)
+to learn more.
+
+
+[[event-name-cond]]
+Event name condition
+~~~~~~~~~~~~~~~~~~~~
+An event{nbsp}__E__ satisfies the event name condition of a recording
+event rule{nbsp}__ER__ if the two following statements are true:
+
+* You specify the option:--all option or, depending on the
+ instrumentation type condition (see the
+ <<inst-point-type-cond,Instrumentation point type condition>> section
+ above) of{nbsp}__ER__, 'NAME' matches:
++
+--
+LTTng tracepoint::
+ The full name of the tracepoint from which LTTng creates{nbsp}__E__.
++
+Note that the full name of a user space tracepoint is
+__PROVIDER__++:++__NAME__, where __PROVIDER__ is the tracepoint provider
+name and __NAME__ is the tracepoint name.
+
+Logging statement::
+ The name of the Java or Python logger from which LTTng
+ creates{nbsp}__E__.
+
+Linux system call::
+ The name of the system call, without any `sys_` prefix, from which
+ LTTng creates{nbsp}__E__.
+--
+
+* You don't specify the option:--exclude=__XNAME__[++,++__XNAME__]...
+ option or, depending on the instrumentation type condition
+ of{nbsp}__ER__, none of the 'XNAME' arguments matches the full name of
+ the user space tracepoint from which LTTng creates{nbsp}__E__.
++
+The option:--exclude option is only available with the option:--userspace
+option.
+
+This condition is only meaningful for the LTTng tracepoint, logging
+statement, and Linux system call instrumentation point types: it's
+always satisfied for the other types.
+
+In all cases, 'NAME' and 'XNAME' are globbing patterns: the `*`
+character means ``match anything''. To match a literal `*` character,
+use :escwc:. To match a literal `,` character, use
+:esccomma:.
+
+IMPORTANT: Make sure to **single-quote** 'NAME' and 'XNAME' when they
+contain the `*` character and when you run the `enable-event` command
+from a shell.
+
+With the LTTng tracepoint, logging statement, and Linux system call
+instrumentation point types, the `enable-event` command creates or
+enables one independent recording event rule per 'NAME' argument
+(non-option, comma-separated). With the option:--all option, the
+`enable-event` command creates or enables a single recording event rule.