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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 | libtraceevent(3) ================ NAME ---- tep_print_field, tep_print_fields, tep_print_num_field, tep_print_func_field - Print the field content. SYNOPSIS -------- [verse] -- *#include <event-parse.h>* *#include <trace-seq.h>* void *tep_print_field*(struct trace_seq pass:[*]_s_, void pass:[*]_data_, struct tep_format_field pass:[*]_field_); void *tep_print_fields*(struct trace_seq pass:[*]_s_, void pass:[*]_data_, int _size_, struct tep_event pass:[*]_event_); int *tep_print_num_field*(struct trace_seq pass:[*]_s_, const char pass:[*]_fmt_, struct tep_event pass:[*]_event_, const char pass:[*]_name_, struct tep_record pass:[*]_record_, int _err_); int *tep_print_func_field*(struct trace_seq pass:[*]_s_, const char pass:[*]_fmt_, struct tep_event pass:[*]_event_, const char pass:[*]_name_, struct tep_record pass:[*]_record_, int _err_); -- DESCRIPTION ----------- These functions print recorded field's data, according to the field's type. The _tep_print_field()_ 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: [verse] -- "field1_name=field1_value field2_name=field2_value ..." -- It iterates all fields of the _event_, and calls _tep_print_field()_ 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_. RETURN VALUE ------------ 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. EXAMPLE ------- [source,c] -- #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(&seq, record->data, 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); } ... -- FILES ----- [verse] -- *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. -- 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 |