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Diffstat (limited to 'tools/lib/traceevent/Documentation/libtraceevent-field_read.txt')
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1 files changed, 81 insertions, 0 deletions
diff --git a/tools/lib/traceevent/Documentation/libtraceevent-field_read.txt b/tools/lib/traceevent/Documentation/libtraceevent-field_read.txt new file mode 100644 index 000000000000..64e9e25d3fd9 --- /dev/null +++ b/tools/lib/traceevent/Documentation/libtraceevent-field_read.txt @@ -0,0 +1,81 @@ +libtraceevent(3) +================ + +NAME +---- +tep_read_number_field - Reads a number from raw data. + +SYNOPSIS +-------- +[verse] +-- +*#include <event-parse.h>* + +int *tep_read_number_field*(struct tep_format_field pass:[*]_field_, const void pass:[*]_data_, unsigned long long pass:[*]_value_); +-- + +DESCRIPTION +----------- +The _tep_read_number_field()_ function reads the value of the _field_ from the +raw _data_ and stores it in the _value_. The function sets the _value_ according +to the endianness of the raw data and the current machine and stores it in +_value_. + +RETURN VALUE +------------ +The _tep_read_number_field()_ function retunrs 0 in case of success, or -1 in +case of an error. + +EXAMPLE +------- +[source,c] +-- +#include <event-parse.h> +... +struct tep_handle *tep = tep_alloc(); +... +struct tep_event *event = tep_find_event_by_name(tep, "timer", "hrtimer_start"); +... +void process_record(struct tep_record *record) +{ + unsigned long long pid; + struct tep_format_field *field_pid = tep_find_common_field(event, "common_pid"); + + if (tep_read_number_field(field_pid, record->data, &pid) != 0) { + /* Failed to get "common_pid" value */ + } +} +... +-- +FILES +----- +[verse] +-- +*event-parse.h* + Header file to include in order to have access to the library APIs. +*-ltraceevent* + Linker switch to add when building a program that uses the library. +-- + +SEE ALSO +-------- +_libtraceevent(3)_, _trace-cmd(1)_ + +AUTHOR +------ +[verse] +-- +*Steven Rostedt* <rostedt@goodmis.org>, author of *libtraceevent*. +*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com>, author of this man page. +-- +REPORTING BUGS +-------------- +Report bugs to <linux-trace-devel@vger.kernel.org> + +LICENSE +------- +libtraceevent is Free Software licensed under the GNU LGPL 2.1 + +RESOURCES +--------- +https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git |