1LIBTRACEEVENT(3) libtraceevent Manual LIBTRACEEVENT(3)
2
6 tep_print_field_content, tep_print_fields, tep_print_num_field,
7 tep_print_func_field, tep_record_print_fields,
8 tep_record_print_selected_fields - Print the field content.
9
11 #include <event-parse.h>
12 #include <trace-seq.h>
13 void tep_print_field_content(struct trace_seq *s, void *data, int size, struct tep_format_field *field);
15 void tep_print_fields(struct trace_seq *s, void *data, int size, struct tep_event *event);
16 int tep_print_num_field(struct trace_seq *s, const char *fmt, struct tep_event *event, const char *name, struct tep_record *record, int err);
17 int tep_print_func_field(struct trace_seq *s, const char *fmt, struct tep_event *event, const char *name, struct tep_record *record, int err);
18 void tep_record_print_fields(struct trace_seq *s, struct tep_record *record, struct tep_event *event);
19 void tep_record_print_selected_fields(struct trace_seq *s, struct tep_record *record, struct tep_event *event, int select_mask);
20
22 These functions print recorded field’s data, according to the field’s
23 type.
24 The tep_print_field_content() function extracts from the recorded raw
26 data value of the field and prints it into s, according to the field
27 type.
28 The tep_print_fields() prints each field name followed by the record’s
30 field value according to the field’s type:
31 "field1_name=field1_value field2_name=field2_value ..."
33 It iterates all fields of the event, and calls
35 tep_print_field_content() for each of them.
36 The tep_print_num_field() function prints a numeric field with given
38 format string. A search is performed in the event for a field with
39 name. If such field is found, its value is extracted from the record
40 and is printed in the s, according to the given format string fmt. If
41 the argument err is non-zero, and an error occures - it is printed in
42 the s.
43 The tep_print_func_field() function prints a function field with given
45 format string. A search is performed in the event for a field with
46 name. If such field is found, its value is extracted from the record.
47 The value is assumed to be a function address, and a search is perform
48 to find the name of this function. The function name (if found) and its
49 address are printed in the s, according to the given format string fmt.
50 If the argument err is non-zero, and an error occures - it is printed
51 in s.
52 The tep_record_print_fields() prints the field’s name followed by its
54 value for all record’s field.
55 The tep_record_print_selected_fields() prints the field’s name followed
57 by its value for selected subset of record field. The fields to be
58 printed are defined by the select_mask bit mask.
59
61 The tep_print_num_field() and tep_print_func_field() functions return 1
62 on success, -1 in case of an error or 0 if the print buffer s is full.
63
65 #include <event-parse.h>
66 #include <trace-seq.h>
67 ...
68 struct tep_handle *tep = tep_alloc();
69 ...
70 struct trace_seq seq;
71 trace_seq_init(&seq);
72 struct tep_event *event = tep_find_event_by_name(tep, "timer", "hrtimer_start");
73 ...
74 void process_record(struct tep_record *record)
75 {
76 struct tep_format_field *field_pid = tep_find_common_field(event, "common_pid");
77 trace_seq_reset(&seq);
79 /* Print the value of "common_pid" */
81 tep_print_field_content(&seq, record->data, record->size, field_pid);
82 /* Print all fields of the "hrtimer_start" event */
84 tep_print_fields(&seq, record->data, record->size, event);
85 /* Print the value of "expires" field with custom format string */
87 tep_print_num_field(&seq, " timer expires in %llu ", event, "expires", record, 0);
88 /* Print the address and the name of "function" field with custom format string */
90 tep_print_func_field(&seq, " timer function is %s ", event, "function", record, 0);
91 }
92 ...
93
95 event-parse.h
96 Header file to include in order to have access to the library APIs.
97 trace-seq.h
98 Header file to include in order to have access to trace sequences related APIs.
99 Trace sequences are used to allow a function to call several other functions
100 to create a string of data to use.
101 -ltraceevent
102 Linker switch to add when building a program that uses the library.
103
105 libtraceevent(3), trace-cmd(1)
106
108 Steven Rostedt <rostedt@goodmis.org[1]>, author of libtraceevent.
109 Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>, author of this man page.
110
112 Report bugs to <linux-trace-devel@vger.kernel.org[3]>
113
115 libtraceevent is Free Software licensed under the GNU LGPL 2.1
116
118 https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/
119
121 1. rostedt@goodmis.org
122 mailto:rostedt@goodmis.org
123 2. tz.stoyanov@gmail.com
125 mailto:tz.stoyanov@gmail.com
126 3. linux-trace-devel@vger.kernel.org
128 mailto:linux-trace-devel@vger.kernel.org
129libtraceevent 1.5.3 04/15/2022 LIBTRACEEVENT(3)