Create man pages for tep_register_print_function() and tep_unregister_print_function()
as part of the libtraceevent APIs.
Signed-off-by: Tzvetomir Stoyanov <tstoyanov@xxxxxxxxxx>
---
.../libtraceevent-reg_print_func.txt | 128 ++++++++++++++++++
1 file changed, 128 insertions(+)
create mode 100644 tools/lib/traceevent/Documentation/libtraceevent-reg_print_func.txt
diff --git a/tools/lib/traceevent/Documentation/libtraceevent-reg_print_func.txt b/tools/lib/traceevent/Documentation/libtraceevent-reg_print_func.txt
new file mode 100644
index 000000000000..59cef18b71f1
--- /dev/null
+++ b/tools/lib/traceevent/Documentation/libtraceevent-reg_print_func.txt
@@ -0,0 +1,128 @@
+libtraceevent(3)
+================
+
+NAME
+----
+tep_register_print_function,tep_unregister_print_function - Registers / Unregisters
+a helper function.
+
+SYNOPSIS
+--------
+[verse]
+--
+*#include <event-parse.h>*
+
+enum *tep_func_arg_type* {
+ TEP_FUNC_ARG_VOID,
+ TEP_FUNC_ARG_INT,
+ TEP_FUNC_ARG_LONG,
+ TEP_FUNC_ARG_STRING,
+ TEP_FUNC_ARG_PTR,
+ TEP_FUNC_ARG_MAX_TYPES
+};
+
+typedef unsigned long long (*pass:[*]tep_func_handler*)(struct trace_seq pass:[*]s, unsigned long long pass:[*]args);
+
+int *tep_register_print_function*(struct tep_handle pass:[*]_tep_, tep_func_handler _func_, enum tep_func_arg_type _ret_type_, char pass:[*]_name_, _..._);
+int *tep_unregister_print_function*(struct tep_handle pass:[*]_tep_, tep_func_handler _func_, char pass:[*]_name_);
+--
+
+DESCRIPTION
+-----------
+Some events may have helper functions in the print format arguments. This allows
+a plugin to dynamically create a way to process one of these functions.
+
+The _tep_register_print_function()_ registers such helper function. The _tep_
+argument is the trace event parser context. The _func_ argument is the address
+of the helper function. The _ret_type_ argument is the return type of the
+helper function, value from the _tep_func_arg_type_ enum. The _name_ is the name
+of the helper function, as seen in the print format arguments. The _..._ is a
+variable list of _tep_func_arg_type_ enums, the _func_ function arguments.
+This list must end with _TEP_FUNC_ARG_VOID_.
+
+The _tep_unregister_print_function()_ unregisters a helper function, previously
+registered with _tep_register_print_function()_. The _tep_ argument is the
+trace event parser context. The _func_ and _name_ arguments are the same, used
+when the helper function was registered.
+
+The _tep_func_handler_ is the type of the helper function. The _s_ argument is
+the trace sequence, it can be used to create a custom string.
+The _args_ is a list of arguments, defined when the helper function was
+registered.
+
+RETURN VALUE
+------------
+The _tep_register_print_function()_ function returns 0 in case of success.
+In case of an error, TEP_ERRNO_... code is returned.
+
+The _tep_unregister_print_function()_ returns 0 in case of success, or -1 in
+case of an error.
+
+EXAMPLE
+-------
+[source,c]
+--
+#include <event-parse.h>
+#include <trace-seq.h>
+...
+struct tep_handle *tep = tep_alloc();
+...
+static long long
+process_custom_helper(struct trace_seq *s, unsigned long long *args)
+{
+ unsigned long long param = args[0];
+ trace_seq_printf(s, "the helper was called, with argument %lld", param);
+ return 0;
+}
+...
+ if ( tep_register_print_function(tep,
+ process_custom_helper,
+ TEP_FUNC_ARG_STRING,
+ "custom_helper",
+ TEP_FUNC_ARG_LONG,
+ TEP_FUNC_ARG_VOID) != 0) {
+ /* Failed to register my process_custom_helper function */
+ }
+...
+ if (tep_unregister_print_function(tep, process_custom_helper,
+ "custom_helper") != 0) {
+ /* Failed to unregister my process_custom_helper function */
+ }
+--
+
+FILES
+-----
+[verse]
+--
+*event-parse.h*
+ Header file to include in order to have access to the library APIs.
+*trace-seq.h*
+ Header file to include in order to have access to trace sequences related APIs.
+ Trace sequences are used to allow a function to call several other functions
+ to create a string of data to use.
+*-ltraceevent*
+ Linker switch to add when building a program that uses the library.
+--
+
+SEE ALSO
+--------
+_libtraceevent(3)_, _trace-cmd(1)_
+
+AUTHOR
+------
+[verse]
+--
+*Steven Rostedt* <rostedt@xxxxxxxxxxx>, author of *libtraceevent*.
+*Tzvetomir Stoyanov* <tz.stoyanov@xxxxxxxxx>, author of this man page.
+--
+REPORTING BUGS
+--------------
+Report bugs to <linux-trace-devel@xxxxxxxxxxxxxxx>
+
+LICENSE
+-------
+libtraceevent is Free Software licensed under the GNU LGPL 2.1
+
+RESOURCES
+---------
+https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
--
2.20.1
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