# tep_print_field_content

## NAME



           tep_print_field_content, tep_print_fields, tep_print_num_field,
           tep_print_func_field, tep_record_print_fields,
           tep_record_print_selected_fields - Print the field content.
    


## SYNOPSIS



           **#include <event-parse.h>**
           **#include <trace-seq.h>**
    
           void **tep_print_field_content**(struct trace_seq *_s_ , void *_data_ , int size, struct tep_format_field *_field_);
           void **tep_print_fields**(struct trace_seq *_s_ , void *_data_ , int _size_ , struct tep_event *_event_);
           int **tep_print_num_field**(struct trace_seq *_s_ , const char *_fmt_ , struct tep_event *_event_ , const char *_name_ , struct tep_record *_record_ , int _err_);
           int **tep_print_func_field**(struct trace_seq *_s_ , const char *_fmt_ , struct tep_event *_event_ , const char *_name_ , struct tep_record *_record_ , int _err_);
           void **tep_record_print_fields**(struct trace_seq *_s_ , struct tep_record *_record_ , struct tep_event *_event_);
           void **tep_record_print_selected_fields**(struct trace_seq *_s_ , struct tep_record *_record_ , struct tep_event *_event_ , int _select_mask_);
    


## DESCRIPTION



           These functions print recorded field’s data, according to the
           field’s type.
    
           The **tep_print_field_content()** 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:
    
               "field1_name=field1_value field2_name=field2_value ..."
    
           It iterates all fields of the _event_ , and calls
           **tep_print_field_content()** 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_.
    
           The **tep_record_print_fields()** prints the field’s name followed by
           its value for all record’s field.
    
           The **tep_record_print_selected_fields()** prints the field’s name
           followed by its value for selected subset of record field. The
           fields to be printed are defined by the _select_mask_ bit mask.
    


## 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



               #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_content(&seq, record->data, record->size, 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



               **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.
    


## LICENSE



           libtraceevent is Free Software licensed under the GNU LGPL 2.1
    


## RESOURCES



           **https://git.kernel.org/pub/scm/libs/libtrace/libtraceevent.git/ **
    


## NOTES



            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
    


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