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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /tools/lib/traceevent/Documentation/libtraceevent-tseq.txt | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 5.10.209.upstream/5.10.209upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/lib/traceevent/Documentation/libtraceevent-tseq.txt')
-rw-r--r-- | tools/lib/traceevent/Documentation/libtraceevent-tseq.txt | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/tools/lib/traceevent/Documentation/libtraceevent-tseq.txt b/tools/lib/traceevent/Documentation/libtraceevent-tseq.txt new file mode 100644 index 000000000..8ac6aa174 --- /dev/null +++ b/tools/lib/traceevent/Documentation/libtraceevent-tseq.txt @@ -0,0 +1,158 @@ +libtraceevent(3) +================ + +NAME +---- +trace_seq_init, trace_seq_destroy, trace_seq_reset, trace_seq_terminate, +trace_seq_putc, trace_seq_puts, trace_seq_printf, trace_seq_vprintf, +trace_seq_do_fprintf, trace_seq_do_printf - +Initialize / destroy a trace sequence. + +SYNOPSIS +-------- +[verse] +-- +*#include <event-parse.h>* +*#include <trace-seq.h>* + +void *trace_seq_init*(struct trace_seq pass:[*]_s_); +void *trace_seq_destroy*(struct trace_seq pass:[*]_s_); +void *trace_seq_reset*(struct trace_seq pass:[*]_s_); +void *trace_seq_terminate*(struct trace_seq pass:[*]_s_); +int *trace_seq_putc*(struct trace_seq pass:[*]_s_, unsigned char _c_); +int *trace_seq_puts*(struct trace_seq pass:[*]_s_, const char pass:[*]_str_); +int *trace_seq_printf*(struct trace_seq pass:[*]_s_, const char pass:[*]_fmt_, _..._); +int *trace_seq_vprintf*(struct trace_seq pass:[*]_s_, const char pass:[*]_fmt_, va_list _args_); +int *trace_seq_do_printf*(struct trace_seq pass:[*]_s_); +int *trace_seq_do_fprintf*(struct trace_seq pass:[*]_s_, FILE pass:[*]_fp_); +-- + +DESCRIPTION +----------- +Trace sequences are used to allow a function to call several other functions +to create a string of data to use. + +The _trace_seq_init()_ function initializes the trace sequence _s_. + +The _trace_seq_destroy()_ function destroys the trace sequence _s_ and frees +all its resources that it had used. + +The _trace_seq_reset()_ function re-initializes the trace sequence _s_. All +characters already written in _s_ will be deleted. + +The _trace_seq_terminate()_ function terminates the trace sequence _s_. It puts +the null character pass:['\0'] at the end of the buffer. + +The _trace_seq_putc()_ function puts a single character _c_ in the trace +sequence _s_. + +The _trace_seq_puts()_ function puts a NULL terminated string _str_ in the +trace sequence _s_. + +The _trace_seq_printf()_ function puts a formated string _fmt _with +variable arguments _..._ in the trace sequence _s_. + +The _trace_seq_vprintf()_ function puts a formated string _fmt _with +list of arguments _args_ in the trace sequence _s_. + +The _trace_seq_do_printf()_ function prints the buffer of trace sequence _s_ to +the standard output stdout. + +The _trace_seq_do_fprintf()_ function prints the buffer of trace sequence _s_ +to the given file _fp_. + +RETURN VALUE +------------ +Both _trace_seq_putc()_ and _trace_seq_puts()_ functions return the number of +characters put in the trace sequence, or 0 in case of an error + +Both _trace_seq_printf()_ and _trace_seq_vprintf()_ functions return 0 if the +trace oversizes the buffer's free space, the number of characters printed, or +a negative value in case of an error. + +Both _trace_seq_do_printf()_ and _trace_seq_do_fprintf()_ functions return the +number of printed characters, or -1 in case of an error. + +EXAMPLE +------- +[source,c] +-- +#include <event-parse.h> +#include <trace-seq.h> +... +struct trace_seq seq; +trace_seq_init(&seq); +... +void foo_seq_print(struct trace_seq *tseq, char *format, ...) +{ + va_list ap; + va_start(ap, format); + if (trace_seq_vprintf(tseq, format, ap) <= 0) { + /* Failed to print in the trace sequence */ + } + va_end(ap); +} + +trace_seq_reset(&seq); + +char *str = " MAN page example"; +if (trace_seq_puts(&seq, str) != strlen(str)) { + /* Failed to put str in the trace sequence */ +} +if (trace_seq_putc(&seq, ':') != 1) { + /* Failed to put ':' in the trace sequence */ +} +if (trace_seq_printf(&seq, " trace sequence: %d", 1) <= 0) { + /* Failed to print in the trace sequence */ +} +foo_seq_print( &seq, " %d\n", 2); + +trace_seq_terminate(&seq); +... + +if (trace_seq_do_printf(&seq) < 0 ) { + /* Failed to print the sequence buffer to the standard output */ +} +FILE *fp = fopen("trace.txt", "w"); +if (trace_seq_do_fprintf(&seq, fp) < 0 ) [ + /* Failed to print the sequence buffer to the trace.txt file */ +} + +trace_seq_destroy(&seq); +... +-- + +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. +*-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 |