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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | EXAMPLE | FILES | SEE ALSO | AUTHOR | REPORTING BUGS | LICENSE | RESOURCES | NOTES | COLOPHON |
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LIBTRACEEVENT(3) libtraceevent Manual LIBTRACEEVENT(3)
tep_print_field_content, tep_print_fields, tep_print_num_field,
tep_print_func_field, tep_record_print_fields,
tep_record_print_selected_fields - Print the field content.
#include <event-parse.h>
#include <trace-seq.h>
void tep_print_field_content(struct trace_seq *s, void *data, int size, struct tep_format_field *field);
void tep_print_fields(struct trace_seq *s, void *data, int size, struct tep_event *event);
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);
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);
void tep_record_print_fields(struct trace_seq *s, struct tep_record *record, struct tep_event *event);
void tep_record_print_selected_fields(struct trace_seq *s, struct tep_record *record, struct tep_event *event, int select_mask);
These functions print recorded field’s data, according to the
field’s type.
The tep_print_field_content() function extracts from the recorded
raw data value of the field and prints it into s, according to
the field type.
The tep_print_fields() prints each field name followed by the
record’s field value according to the field’s type:
"field1_name=field1_value field2_name=field2_value ..."
It iterates all fields of the event, and calls
tep_print_field_content() for each of them.
The tep_print_num_field() function prints a numeric field with
given format string. A search is performed in the event for a
field with name. If such field is found, its value is extracted
from the record and is printed in the s, according to the given
format string fmt. If the argument err is non-zero, and an error
occures - it is printed in the s.
The tep_print_func_field() function prints a function field with
given format string. A search is performed in the event for a
field with name. If such field is found, its value is extracted
from the record. The value is assumed to be a function address,
and a search is perform to find the name of this function. The
function name (if found) and its address are printed in the s,
according to the given format string fmt. If the argument err is
non-zero, and an error occures - it is printed in s.
The tep_record_print_fields() prints the field’s name followed by
its value for all record’s field.
The tep_record_print_selected_fields() prints the field’s name
followed by its value for selected subset of record field. The
fields to be printed are defined by the select_mask bit mask.
The tep_print_num_field() and tep_print_func_field() functions
return 1 on success, -1 in case of an error or 0 if the print
buffer s is full.
#include <event-parse.h>
#include <trace-seq.h>
...
struct tep_handle *tep = tep_alloc();
...
struct trace_seq seq;
trace_seq_init(&seq);
struct tep_event *event = tep_find_event_by_name(tep, "timer", "hrtimer_start");
...
void process_record(struct tep_record *record)
{
struct tep_format_field *field_pid = tep_find_common_field(event, "common_pid");
trace_seq_reset(&seq);
/* Print the value of "common_pid" */
tep_print_field_content(&seq, record->data, record->size, field_pid);
/* Print all fields of the "hrtimer_start" event */
tep_print_fields(&seq, record->data, record->size, event);
/* Print the value of "expires" field with custom format string */
tep_print_num_field(&seq, " timer expires in %llu ", event, "expires", record, 0);
/* Print the address and the name of "function" field with custom format string */
tep_print_func_field(&seq, " timer function is %s ", event, "function", record, 0);
}
...
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.
libtraceevent(3), trace-cmd(1)
Steven Rostedt <[email protected][1]>, author of libtraceevent.
Tzvetomir Stoyanov <[email protected][2]>, author of this man page.
Report bugs to <[email protected][3]>
libtraceevent is Free Software licensed under the GNU LGPL 2.1
https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/
1. [email protected]
mailto:[email protected]
2. [email protected]
mailto:[email protected]
3. [email protected]
mailto:[email protected]
This page is part of the libtraceevent (Linux kernel trace event
library) project. Information about the project can be found at
⟨https://www.trace-cmd.org/⟩. If you have a bug report for this
manual page, see ⟨https://www.trace-cmd.org/⟩. This page was
obtained from the project's upstream Git repository
⟨https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git⟩
on 2024-06-14. (At that time, the date of the most recent commit
that was found in the repository was 2024-05-17.) If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to [email protected]
libtraceevent 1.7.3 09/24/2023 LIBTRACEEVENT(3)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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