libtracefs(3) ============= NAME ---- tracefs_binary_init, tracefs_binary_close, tracefs_binary_write - Open, close and write binary data in the trace buffer. SYNOPSIS -------- [verse] -- *#include * int *tracefs_binary_init*(struct tracefs_instance pass:[*]_instance_); int *tracefs_binary_write*(struct tracefs_instance pass:[*]_instance_, void pass:[*]_data_, int _len_); void *tracefs_binary_close*(struct tracefs_instance pass:[*]_instance_); -- DESCRIPTION ----------- Set of functions to write binary data in the trace buffer. See Documentation/trace/ftrace.rst from the Linux kernel tree for more information about writing data from user space in the trace buffer. All these APIs have _instance_ as a first argument. If NULL is passed as _instance_, the top trace instance is used. The *tracefs_binary_init()* function initializes the library for writing into the trace buffer of the selected _instance_. It is not mandatory to call this API before writing data, the *tracefs_binary_write()* will call it automatically, if the library is not yet initialized. But calling *tracefs_binary_init()* in advance will speed up the writing. The *tracefs_binary_write()* function writes a binary data in the trace buffer of the selected _instance_. The _data_ points to the data with length _len_, that is going to be written in the trace buffer. The *tracefs_binary_close()* function closes the resources, used by the library for writing in the trace buffer of the selected instance. RETURN VALUE ------------ The *tracefs_binary_init()*, and *tracefs_binary_write()* functions return 0 if the operation is successful, or -1 in case of an error. EXAMPLE ------- [source,c] -- #include if (tracefs_binary_init(NULL) < 0) { /* Failed to initialize the library for writing in the trace buffer of the top trace instance */ } unsigned int data = 0xdeadbeef; if (tracefs_binary_write(NULL, &data, sizeof(data)) < 0) { /* Failed to write in the trace buffer */ } tracefs_binary_close(); -- FILES ----- [verse] -- *tracefs.h* Header file to include in order to have access to the library APIs. *-ltracefs* Linker switch to add when building a program that uses the library. -- SEE ALSO -------- *libtracefs*(3), *libtraceevent*(3), *trace-cmd*(1), Documentation/trace/ftrace.rst from the Linux kernel tree AUTHOR ------ [verse] -- *Steven Rostedt* *Tzvetomir Stoyanov* -- REPORTING BUGS -------------- Report bugs to LICENSE ------- libtracefs is Free Software licensed under the GNU LGPL 2.1 RESOURCES --------- https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/ COPYING ------- Copyright \(C) 2021 VMware, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).