1libtraceevent(3) 2================ 3 4NAME 5---- 6tep_find_common_field, tep_find_field, tep_find_any_field - 7Search for a field in an event. 8 9SYNOPSIS 10-------- 11[verse] 12-- 13*#include <event-parse.h>* 14 15struct tep_format_field pass:[*]*tep_find_common_field*(struct tep_event pass:[*]_event_, const char pass:[*]_name_); 16struct tep_format_field pass:[*]*tep_find_field*(struct tep_event_ormat pass:[*]_event_, const char pass:[*]_name_); 17struct tep_format_field pass:[*]*tep_find_any_field*(struct tep_event pass:[*]_event_, const char pass:[*]_name_); 18-- 19 20DESCRIPTION 21----------- 22These functions search for a field with given name in an event. The field 23returned can be used to find the field content from within a data record. 24 25The _tep_find_common_field()_ function searches for a common field with _name_ 26in the _event_. 27 28The _tep_find_field()_ function searches for an event specific field with 29_name_ in the _event_. 30 31The _tep_find_any_field()_ function searches for any field with _name_ in the 32_event_. 33 34RETURN VALUE 35------------ 36The _tep_find_common_field(), _tep_find_field()_ and _tep_find_any_field()_ 37functions return a pointer to the found field, or NULL in case there is no field 38with the requested name. 39 40EXAMPLE 41------- 42[source,c] 43-- 44#include <event-parse.h> 45... 46void get_htimer_info(struct tep_handle *tep, struct tep_record *record) 47{ 48 struct tep_format_field *field; 49 struct tep_event *event; 50 long long softexpires; 51 int mode; 52 int pid; 53 54 event = tep_find_event_by_name(tep, "timer", "hrtimer_start"); 55 56 field = tep_find_common_field(event, "common_pid"); 57 if (field == NULL) { 58 /* Cannot find "common_pid" field in the event */ 59 } else { 60 /* Get pid from the data record */ 61 pid = tep_read_number(tep, record->data + field->offset, 62 field->size); 63 } 64 65 field = tep_find_field(event, "softexpires"); 66 if (field == NULL) { 67 /* Cannot find "softexpires" event specific field in the event */ 68 } else { 69 /* Get softexpires parameter from the data record */ 70 softexpires = tep_read_number(tep, record->data + field->offset, 71 field->size); 72 } 73 74 field = tep_find_any_field(event, "mode"); 75 if (field == NULL) { 76 /* Cannot find "mode" field in the event */ 77 } else 78 { 79 /* Get mode parameter from the data record */ 80 mode = tep_read_number(tep, record->data + field->offset, 81 field->size); 82 } 83} 84... 85-- 86 87FILES 88----- 89[verse] 90-- 91*event-parse.h* 92 Header file to include in order to have access to the library APIs. 93*-ltraceevent* 94 Linker switch to add when building a program that uses the library. 95-- 96 97SEE ALSO 98-------- 99_libtraceevent(3)_, _trace-cmd(1)_ 100 101AUTHOR 102------ 103[verse] 104-- 105*Steven Rostedt* <rostedt@goodmis.org>, author of *libtraceevent*. 106*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page. 107-- 108REPORTING BUGS 109-------------- 110Report bugs to <linux-trace-devel@vger.kernel.org> 111 112LICENSE 113------- 114libtraceevent is Free Software licensed under the GNU LGPL 2.1 115 116RESOURCES 117--------- 118https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 119