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NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |EXAMPLE |FILES |SEE ALSO |AUTHOR |REPORTING BUGS |LICENSE |RESOURCES |NOTES |COLOPHON | |
LIBTRACEEVENT(3) libtraceevent ManualLIBTRACEEVENT(3)tep_get_any_field_val, tep_get_common_field_val, tep_get_field_val, tep_get_field_raw - Get value of a field.
#include <event-parse.h>#include <trace-seq.h> inttep_get_any_field_val(struct trace_seq *s, struct tep_event *event, const char *name, struct tep_record *record, unsigned long long *val, interr); inttep_get_common_field_val(struct trace_seq *s, struct tep_event *event, const char *name, struct tep_record *record, unsigned long long *val, interr); inttep_get_field_val(struct trace_seq *s, struct tep_event *event, const char *name, struct tep_record *record, unsigned long long *val, interr); void *tep_get_field_raw(struct trace_seq *s, struct tep_event *event, const char *name, struct tep_record *record, int *len, interr);
These functions can be used to find a field and retrieve its value. Thetep_get_any_field_val()function searches in therecord for a field withname, part of theevent. If the field is found, its value is stored inval. If there is an error anderr is not zero, then an error string is written intos. Thetep_get_common_field_val()function does the same astep_get_any_field_val(), but searches only in the common fields. This works for any event as all events include the common fields. Thetep_get_field_val()function does the same astep_get_any_field_val(), but searches only in the event specific fields. Thetep_get_field_raw()function searches in therecord for a field withname, part of theevent. If the field is found, a pointer to where the field exists in the record’s raw data is returned. The size of the data is stored inlen. If there is an error anderr is not zero, then an error string is written intos.
Thetep_get_any_field_val(),tep_get_common_field_val()andtep_get_field_val()functions return 0 on success, or -1 in case of an error. Thetep_get_field_raw()function returns a pointer to field’s raw data, and places the length of this data inlen. In case of an error NULL is returned.
#include <event-parse.h> #include <trace-seq.h> ... struct tep_handle *tep = tep_alloc(); ... struct tep_event *event = tep_find_event_by_name(tep, "kvm", "kvm_exit"); ... void process_record(struct tep_record *record) { int len; char *comm; struct tep_event *event; unsigned long long val; event = tep_find_event_by_record(tep, record); if (event != NULL) { if (tep_get_common_field_val(NULL, event, "common_type", record, &val, 0) == 0) { /* Got the value of common type field */ } if (tep_get_field_val(NULL, event, "pid", record, &val, 0) == 0) { /* Got the value of pid specific field */ } comm = tep_get_field_raw(NULL, event, "comm", record, &len, 0); if (comm != NULL) { /* Got a pointer to the comm event specific field */ } } }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<rostedt@goodmis.org[1]>, author oflibtraceevent.Tzvetomir Stoyanov<tz.stoyanov@gmail.com[2]>, author of this man page.
Report bugs to <linux-trace-devel@vger.kernel.org[3]>
libtraceevent is Free Software licensed under the GNU LGPL 2.1
https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/
1. rostedt@goodmis.org mailto:rostedt@goodmis.org 2. tz.stoyanov@gmail.com mailto:tz.stoyanov@gmail.com 3. linux-trace-devel@vger.kernel.org mailto:linux-trace-devel@vger.kernel.org
This page is part of thelibtraceevent (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 2025-08-11. (At that time, the date of the most recent commit that was found in the repository was 2025-05-30.) 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 isnot part of the original manual page), send a mail to man-pages@man7.orglibtraceevent 1.7.3 09/24/2023LIBTRACEEVENT(3)HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |