| libtracecmd(3) |
| ============= |
| |
| NAME |
| ---- |
| tracecmd_buffer_instances, tracecmd_buffer_instance_name, tracecmd_buffer_instance_handle |
| - Read tracing instances from a trace file. |
| |
| SYNOPSIS |
| -------- |
| [verse] |
| -- |
| *#include <trace-cmd.h>* |
| |
| int *tracecmd_buffer_instances*(struct tracecmd_input pass:[*]_handle_); |
| const char pass:[*]*tracecmd_buffer_instance_name*(struct tracecmd_input pass:[*]_handle_, int _indx_); |
| struct tracecmd_input pass:[*]*tracecmd_buffer_instance_handle*(struct tracecmd_input pass:[*]_handle_, int _indx_); |
| -- |
| |
| DESCRIPTION |
| ----------- |
| This set of APIs can be used to get information and read tracing data |
| from tracing instances stored in a trace file. |
| |
| The _tracecmd_buffer_instances()_ function gets the number of tracing |
| instances recorded in a trace file. The top instance is not counted. |
| The _handle_ is a tracecmd_input handler returned by |
| _tracecmd_open_head()_. |
| |
| The _tracecmd_buffer_instance_name()_ function gets the name of the |
| tracing instance with given index _indx_, recorded in a trace file. |
| The _indx_ is a number in the interval [0 .. count-1], where count |
| is the number returned by _tracecmd_buffer_instances()_. The _handle_ |
| is a tracecmd_input handler returned by _tracecmd_open_head()_. |
| |
| The _tracecmd_buffer_instance_handle()_ allocates and initializes a |
| tracecmd_input handle, associated with trace instance with index |
| _indx_ from a trace file. The _handle_ is a tracecmd_input handler |
| returned by _tracecmd_open_head()_. The _indx_ is a number in the |
| interval [0 .. count-1], where count is the number returned by |
| _tracecmd_buffer_instances()_. |
| |
| RETURN VALUE |
| ------------ |
| The _tracecmd_buffer_instances()_ function returns the number of tracing |
| instances recorded in a trace file. |
| |
| The _tracecmd_buffer_instance_name()_ function returns a string, the name |
| of a tracing instance, or NULL in case of an error The string must *not* |
| be freed. |
| |
| The _tracecmd_buffer_instance_handle()_ function returns a pointer to |
| newly allocated tracecmd_input handler or NULL in case if an error. The |
| returned handler must be closed by _tracecmd_close()(3)_ |
| |
| EXAMPLE |
| ------- |
| [source,c] |
| -- |
| #include <trace-cmd.h> |
| ... |
| struct tracecmd_input *handle = tracecmd_open_head("trace.dat"); |
| if (!handle) { |
| /* Failed to open trace.dat file */ |
| } |
| ... |
| int num = tracecmd_buffer_instances(handle); |
| |
| while(num) { |
| struct tracecmd_input *h; |
| char *name; |
| |
| name = tracecmd_buffer_instance_name(handle, num); |
| if (!name) { |
| /* Failed to get name of instance num */ |
| } |
| h = tracecmd_buffer_instance_handle(handle, num); |
| if (!h) { |
| /* Failed to initialize handler for instance num */ |
| } |
| |
| ... |
| tracecmd_close(h); |
| num--; |
| } |
| ... |
| tracecmd_close(handle); |
| |
| -- |
| FILES |
| ----- |
| [verse] |
| -- |
| *trace-cmd.h* |
| Header file to include in order to have access to the library APIs. |
| *-ltracecmd* |
| Linker switch to add when building a program that uses the library. |
| -- |
| |
| SEE ALSO |
| -------- |
| _libtracefs(3)_, |
| _libtraceevent(3)_, |
| _trace-cmd(1)_ |
| _trace-cmd.dat(5)_ |
| |
| AUTHOR |
| ------ |
| [verse] |
| -- |
| *Steven Rostedt* <[email protected]> |
| *Tzvetomir Stoyanov* <[email protected]> |
| -- |
| REPORTING BUGS |
| -------------- |
| Report bugs to <[email protected]> |
| |
| LICENSE |
| ------- |
| libtracecmd is Free Software licensed under the GNU LGPL 2.1 |
| |
| RESOURCES |
| --------- |
| https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/ |
| |
| COPYING |
| ------- |
| Copyright \(C) 2020 VMware, Inc. Free use of this software is granted under |
| the terms of the GNU Public License (GPL). |
