POSIX_TRACE_ATTR_GETLOGSIZEPOSIX Programmer's MPOSIX_TRACE_ATTR_GETLOGSIZE(3P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding
Linux manual page for details of Linux behavior), or the interface may
not be implemented on Linux.
NAME
posix_trace_attr_getlogsize, posix_trace_attr_getmaxdatasize,
posix_trace_attr_getmaxsystemeventsize, posix_trace_attr_get‐
maxusereventsize, posix_trace_attr_getstreamsize, posix_trace_attr_set‐
logsize, posix_trace_attr_setmaxdatasize, posix_trace_attr_setstream‐
size - retrieve and set trace stream size attributes (TRACING)
SYNOPSIS
#include <sys/types.h>
#include <trace.h>
int posix_trace_attr_getlogsize(const trace_attr_t *restrict attr,
size_t *restrict logsize);
int posix_trace_attr_getmaxdatasize(const trace_attr_t *restrict attr,
size_t *restrict maxdatasize);
int posix_trace_attr_getmaxsystemeventsize(
const trace_attr_t *restrict attr,
size_t *restrict eventsize);
int posix_trace_attr_getmaxusereventsize(
const trace_attr_t *restrict attr,
size_t data_len, size_t *restrict eventsize);
int posix_trace_attr_getstreamsize(const trace_attr_t *restrict attr,
size_t *restrict streamsize);
int posix_trace_attr_setlogsize(trace_attr_t *attr,
size_t logsize);
int posix_trace_attr_setmaxdatasize(trace_attr_t *attr,
size_t maxdatasize);
int posix_trace_attr_setstreamsize(trace_attr_t *attr,
size_t streamsize);
DESCRIPTION
The posix_trace_attr_getlogsize() function shall copy the log size, in
bytes, from the log-max-size attribute of the attributes object pointed
to by the attr argument into the variable pointed to by the logsize
argument. This log size is the maximum total of bytes that shall be
allocated for system and user trace events in the trace log. The
default value for the log-max-size attribute is implementation-defined.
The posix_trace_attr_setlogsize() function shall set the maximum
allowed size, in bytes, in the log-max-size attribute of the attributes
object pointed to by the attr argument, using the size value supplied
by the logsize argument.
The trace log size shall be used if the log-full-policy attribute is
set to POSIX_TRACE_LOOP or POSIX_TRACE_UNTIL_FULL. If the log-full-
policy attribute is set to POSIX_TRACE_APPEND, the implementation shall
ignore the log-max-size attribute.
The posix_trace_attr_getmaxdatasize() function shall copy the maximum
user trace event data size, in bytes, from the max-data-size attribute
of the attributes object pointed to by the attr argument into the vari‐
able pointed to by the maxdatasize argument. The default value for the
max-data-size attribute is implementation-defined.
The posix_trace_attr_getmaxsystemeventsize() function shall calculate
the maximum memory size, in bytes, required to store a single system
trace event. This value is calculated for the trace stream attributes
object pointed to by the attr argument and is returned in the variable
pointed to by the eventsize argument.
The values returned as the maximum memory sizes of the user and system
trace events shall be such that if the sum of the maximum memory sizes
of a set of the trace events that may be recorded in a trace stream is
less than or equal to the stream-min-size attribute of that trace
stream, the system provides the necessary resources for recording all
those trace events, without loss.
The posix_trace_attr_getmaxusereventsize() function shall calculate the
maximum memory size, in bytes, required to store a single user trace
event generated by a call to posix_trace_event() with a data_len param‐
eter equal to the data_len value specified in this call. This value is
calculated for the trace stream attributes object pointed to by the
attr argument and is returned in the variable pointed to by the event‐
size argument.
The posix_trace_attr_getstreamsize() function shall copy the stream
size, in bytes, from the stream-min-size attribute of the attributes
object pointed to by the attr argument into the variable pointed to by
the streamsize argument.
This stream size is the current total memory size reserved for system
and user trace events in the trace stream. The default value for the
stream-min-size attribute is implementation-defined. The stream size
refers to memory used to store trace event records. Other stream data
(for example, trace attribute values) shall not be included in this
size.
The posix_trace_attr_setmaxdatasize() function shall set the maximum
allowed size, in bytes, in the max-data-size attribute of the
attributes object pointed to by the attr argument, using the size value
supplied by the maxdatasize argument. This maximum size is the maximum
allowed size for the user data argument which may be passed to
posix_trace_event(). The implementation shall be allowed to truncate
data passed to trace_user_event which is longer than maxdatasize.
The posix_trace_attr_setstreamsize() function shall set the minimum
allowed size, in bytes, in the stream-min-size attribute of the
attributes object pointed to by the attr argument, using the size value
supplied by the streamsize argument.
RETURN VALUE
Upon successful completion, these functions shall return a value of
zero. Otherwise, they shall return the corresponding error number.
The posix_trace_attr_getlogsize() function stores the maximum trace log
allowed size in the object pointed to by logsize, if successful.
The posix_trace_attr_getmaxdatasize() function stores the maximum trace
event record memory size in the object pointed to by maxdatasize, if
successful.
The posix_trace_attr_getmaxsystemeventsize() function stores the maxi‐
mum memory size to store a single system trace event in the object
pointed to by eventsize, if successful.
The posix_trace_attr_getmaxusereventsize() function stores the maximum
memory size to store a single user trace event in the object pointed to
by eventsize, if successful.
The posix_trace_attr_getstreamsize() function stores the maximum trace
stream allowed size in the object pointed to by streamsize, if success‐
ful.
ERRORS
These functions may fail if:
EINVAL The value specified by one of the arguments is invalid.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSOposix_trace_attr_init(), posix_trace_create(), posix_trace_event(),
posix_trace_get_attr(), the Base Definitions volume of
IEEE Std 1003.1-2001, <sys/types.h>, <trace.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 POSIX_TRACE_ATTR_GETLOGSIZE(3P)
