libtraceevent-field_read.txt (1814B)
1libtraceevent(3) 2================ 3 4NAME 5---- 6tep_read_number_field - Reads a number from raw data. 7 8SYNOPSIS 9-------- 10[verse] 11-- 12*#include <event-parse.h>* 13 14int *tep_read_number_field*(struct tep_format_field pass:[*]_field_, const void pass:[*]_data_, unsigned long long pass:[*]_value_); 15-- 16 17DESCRIPTION 18----------- 19The _tep_read_number_field()_ function reads the value of the _field_ from the 20raw _data_ and stores it in the _value_. The function sets the _value_ according 21to the endianness of the raw data and the current machine and stores it in 22_value_. 23 24RETURN VALUE 25------------ 26The _tep_read_number_field()_ function retunrs 0 in case of success, or -1 in 27case of an error. 28 29EXAMPLE 30------- 31[source,c] 32-- 33#include <event-parse.h> 34... 35struct tep_handle *tep = tep_alloc(); 36... 37struct tep_event *event = tep_find_event_by_name(tep, "timer", "hrtimer_start"); 38... 39void process_record(struct tep_record *record) 40{ 41 unsigned long long pid; 42 struct tep_format_field *field_pid = tep_find_common_field(event, "common_pid"); 43 44 if (tep_read_number_field(field_pid, record->data, &pid) != 0) { 45 /* Failed to get "common_pid" value */ 46 } 47} 48... 49-- 50FILES 51----- 52[verse] 53-- 54*event-parse.h* 55 Header file to include in order to have access to the library APIs. 56*-ltraceevent* 57 Linker switch to add when building a program that uses the library. 58-- 59 60SEE ALSO 61-------- 62_libtraceevent(3)_, _trace-cmd(1)_ 63 64AUTHOR 65------ 66[verse] 67-- 68*Steven Rostedt* <rostedt@goodmis.org>, author of *libtraceevent*. 69*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page. 70-- 71REPORTING BUGS 72-------------- 73Report bugs to <linux-trace-devel@vger.kernel.org> 74 75LICENSE 76------- 77libtraceevent is Free Software licensed under the GNU LGPL 2.1 78 79RESOURCES 80--------- 81https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git