'\" t
.\"     Title: libtraceevent
.\"    Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 02/15/2021
.\"    Manual: libtraceevent Manual
.\"    Source: libtraceevent 1.1.2
.\"  Language: English
.\"
.TH "LIBTRACEEVENT" "3" "02/15/2021" "libtraceevent 1\&.1\&.2" "libtraceevent Manual"
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.nh
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.\" * MAIN CONTENT STARTS HERE *
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.SH "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\&.
.SH "SYNOPSIS"
.sp
.nf
\fB#include <event\-parse\&.h>\fR
\fB#include <trace\-seq\&.h>\fR

void \fBtrace_seq_init\fR(struct trace_seq *\fIs\fR);
void \fBtrace_seq_destroy\fR(struct trace_seq *\fIs\fR);
void \fBtrace_seq_reset\fR(struct trace_seq *\fIs\fR);
void \fBtrace_seq_terminate\fR(struct trace_seq *\fIs\fR);
int \fBtrace_seq_putc\fR(struct trace_seq *\fIs\fR, unsigned char \fIc\fR);
int \fBtrace_seq_puts\fR(struct trace_seq *\fIs\fR, const char *\fIstr\fR);
int \fBtrace_seq_printf\fR(struct trace_seq *\fIs\fR, const char *\fIfmt\fR, \fI\&...\fR);
int \fBtrace_seq_vprintf\fR(struct trace_seq *\fIs\fR, const char *\fIfmt\fR, va_list \fIargs\fR);
int \fBtrace_seq_do_printf\fR(struct trace_seq *\fIs\fR);
int \fBtrace_seq_do_fprintf\fR(struct trace_seq *\fIs\fR, FILE *\fIfp\fR);
.fi
.SH "DESCRIPTION"
.sp
Trace sequences are used to allow a function to call several other functions to create a string of data to use\&.
.sp
The \fItrace_seq_init()\fR function initializes the trace sequence \fIs\fR\&.
.sp
The \fItrace_seq_destroy()\fR function destroys the trace sequence \fIs\fR and frees all its resources that it had used\&.
.sp
The \fItrace_seq_reset()\fR function re\-initializes the trace sequence \fIs\fR\&. All characters already written in \fIs\fR will be deleted\&.
.sp
The \fItrace_seq_terminate()\fR function terminates the trace sequence \fIs\fR\&. It puts the null character \*(Aq\e0\*(Aq at the end of the buffer\&.
.sp
The \fItrace_seq_putc()\fR function puts a single character \fIc\fR in the trace sequence \fIs\fR\&.
.sp
The \fItrace_seq_puts()\fR function puts a NULL terminated string \fIstr\fR in the trace sequence \fIs\fR\&.
.sp
The \fItrace_seq_printf()\fR function puts a formated string \fIfmt _with variable arguments _\&...\fR in the trace sequence \fIs\fR\&.
.sp
The \fItrace_seq_vprintf()\fR function puts a formated string \fIfmt _with list of arguments _args\fR in the trace sequence \fIs\fR\&.
.sp
The \fItrace_seq_do_printf()\fR function prints the buffer of trace sequence \fIs\fR to the standard output stdout\&.
.sp
The \fItrace_seq_do_fprintf()\fR function prints the buffer of trace sequence \fIs\fR to the given file \fIfp\fR\&.
.SH "RETURN VALUE"
.sp
Both \fItrace_seq_putc()\fR and \fItrace_seq_puts()\fR functions return the number of characters put in the trace sequence, or 0 in case of an error
.sp
Both \fItrace_seq_printf()\fR and \fItrace_seq_vprintf()\fR functions return 0 if the trace oversizes the buffer\(cqs free space, the number of characters printed, or a negative value in case of an error\&.
.sp
Both \fItrace_seq_do_printf()\fR and \fItrace_seq_do_fprintf()\fR functions return the number of printed characters, or \-1 in case of an error\&.
.SH "EXAMPLE"
.sp
.if n \{\
.RS 4
.\}
.nf
#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, \*(Aq:\*(Aq) != 1) {
        /* Failed to put \*(Aq:\*(Aq 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\en", 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);
\&.\&.\&.
.fi
.if n \{\
.RE
.\}
.SH "FILES"
.sp
.if n \{\
.RS 4
.\}
.nf
\fBevent\-parse\&.h\fR
        Header file to include in order to have access to the library APIs\&.
\fBtrace\-seq\&.h\fR
        Header file to include in order to have access to trace sequences related APIs\&.
\fB\-ltraceevent\fR
        Linker switch to add when building a program that uses the library\&.
.fi
.if n \{\
.RE
.\}
.SH "SEE ALSO"
.sp
\fIlibtraceevent(3)\fR, \fItrace\-cmd(1)\fR
.SH "AUTHOR"
.sp
.if n \{\
.RS 4
.\}
.nf
\fBSteven Rostedt\fR <\m[blue]\fBrostedt@goodmis\&.org\fR\m[]\&\s-2\u[1]\d\s+2>, author of \fBlibtraceevent\fR\&.
\fBTzvetomir Stoyanov\fR <\m[blue]\fBtz\&.stoyanov@gmail\&.com\fR\m[]\&\s-2\u[2]\d\s+2>, author of this man page\&.
.fi
.if n \{\
.RE
.\}
.SH "REPORTING BUGS"
.sp
Report bugs to <\m[blue]\fBlinux\-trace\-devel@vger\&.kernel\&.org\fR\m[]\&\s-2\u[3]\d\s+2>
.SH "LICENSE"
.sp
libtraceevent is Free Software licensed under the GNU LGPL 2\&.1
.SH "RESOURCES"
.sp
\m[blue]\fBhttps://git\&.kernel\&.org/pub/scm/libs/libtrace/libtraceevent\&.git/\fR\m[]
.SH "NOTES"
.IP " 1." 4
rostedt@goodmis.org
.RS 4
\%mailto:rostedt@goodmis.org
.RE
.IP " 2." 4
tz.stoyanov@gmail.com
.RS 4
\%mailto:tz.stoyanov@gmail.com
.RE
.IP " 3." 4
linux-trace-devel@vger.kernel.org
.RS 4
\%mailto:linux-trace-devel@vger.kernel.org
.RE