| LIBTRACECMD(3) | libtracefs Manual | LIBTRACECMD(3) |
tracecmd_buffer_instances, tracecmd_buffer_instance_name, tracecmd_buffer_instance_handle - Read tracing instances from a trace file.
#include <trace-cmd.h> int tracecmd_buffer_instances(struct tracecmd_input *handle); const char *tracecmd_buffer_instance_name(struct tracecmd_input *handle, int indx); struct tracecmd_input *tracecmd_buffer_instance_handle(struct tracecmd_input *handle, int indx);
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().
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)
#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);
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.
libtracefs(3), libtraceevent(3), trace-cmd(1) trace-cmd.dat(5)
Steven Rostedt <rostedt@goodmis.org[1]> Tzvetomir Stoyanov <tz.stoyanov@gmail.com[2]>
Report bugs to <linux-trace-devel@vger.kernel.org[3]>
libtracecmd is Free Software licensed under the GNU LGPL 2.1
https://git.kernel.org/pub/scm/utils/trace-cmd/trace-cmd.git/
Copyright (C) 2020 VMware, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).
| 01/22/2023 | libtracefs |