получить и установить поведение потока трассировки (TRACING) (retrieve and set the behavior of a trace stream (TRACING))
Пролог (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.
Имя (Name)
posix_trace_attr_getinherited, posix_trace_attr_getlogfullpolicy,
posix_trace_attr_getstreamfullpolicy,
posix_trace_attr_setinherited, posix_trace_attr_setlogfullpolicy,
posix_trace_attr_setstreamfullpolicy — retrieve and set the
behavior of a trace stream (TRACING)
Синопсис (Synopsis)
#include <trace.h>
int posix_trace_attr_getinherited(const trace_attr_t *restrict attr,
int *restrict inheritancepolicy);
int posix_trace_attr_getlogfullpolicy(const trace_attr_t *restrict attr,
int *restrict logpolicy);
int posix_trace_attr_getstreamfullpolicy(const trace_attr_t *restrict
attr, int *restrict streampolicy);
int posix_trace_attr_setinherited(trace_attr_t *attr,
int inheritancepolicy);
int posix_trace_attr_setlogfullpolicy(trace_attr_t *attr,
int logpolicy);
int posix_trace_attr_setstreamfullpolicy(trace_attr_t *attr,
int streampolicy);
Описание (Description)
The posix_trace_attr_getinherited() and
posix_trace_attr_setinherited() functions, respectively, shall
get and set the inheritance policy stored in the inheritance
attribute for traced processes across the fork() and spawn()
operations. The inheritance attribute of the attributes object
pointed to by the attr argument shall be set to one of the
following values defined by manifest constants in the <trace.h>
header:
POSIX_TRACE_CLOSE_FOR_CHILD
After a fork() or spawn() operation, the child shall not be
traced, and tracing of the parent shall continue.
POSIX_TRACE_INHERITED
After a fork() or spawn() operation, if the parent is being
traced, its child shall be concurrently traced using the
same trace stream.
The default value for the inheritance attribute is
POSIX_TRACE_CLOSE_FOR_CHILD.
The posix_trace_attr_getlogfullpolicy() and
posix_trace_attr_setlogfullpolicy() functions, respectively,
shall get and set the trace log full policy stored in the log-
full-policy attribute of the attributes object pointed to by the
attr argument.
The log-full-policy attribute shall be set to one of the
following values defined by manifest constants in the <trace.h>
header:
POSIX_TRACE_LOOP
The trace log shall loop until the associated trace stream
is stopped. This policy means that when the trace log gets
full, the file system shall reuse the resources allocated
to the oldest trace events that were recorded. In this way,
the trace log will always contain the most recent trace
events flushed.
POSIX_TRACE_UNTIL_FULL
The trace stream shall be flushed to the trace log until
the trace log is full. This condition can be deduced from
the posix_log_full_status member status (see the
posix_trace_status_info structure defined in <trace.h>).
The last recorded trace event shall be the POSIX_TRACE_STOP
trace event.
POSIX_TRACE_APPEND
The associated trace stream shall be flushed to the trace
log without log size limitation. If the application
specifies POSIX_TRACE_APPEND, the implementation shall
ignore the log-max-size attribute.
The default value for the log-full-policy attribute is
POSIX_TRACE_LOOP.
The posix_trace_attr_getstreamfullpolicy() and
posix_trace_attr_setstreamfullpolicy() functions, respectively,
shall get and set the trace stream full policy stored in the
stream-full-policy attribute of the attributes object pointed to
by the attr argument.
The stream-full-policy attribute shall be set to one of the
following values defined by manifest constants in the <trace.h>
header:
POSIX_TRACE_LOOP
The trace stream shall loop until explicitly stopped by the
posix_trace_stop() function. This policy means that when
the trace stream is full, the trace system shall reuse the
resources allocated to the oldest trace events recorded. In
this way, the trace stream will always contain the most
recent trace events recorded.
POSIX_TRACE_UNTIL_FULL
The trace stream will run until the trace stream resources
are exhausted. Then the trace stream will stop. This
condition can be deduced from posix_stream_status and
posix_stream_full_status (see the posix_trace_status_info
structure defined in <trace.h>). When this trace stream is
read, a POSIX_TRACE_STOP trace event shall be reported
after reporting the last recorded trace event. The trace
system shall reuse the resources allocated to any trace
events already reported—see the
posix_trace_getnext_event(),
posix_trace_trygetnext_event(), and
posix_trace_timedgetnext_event() functions—or already
flushed for an active trace stream with log if the Trace
Log option is supported; see the posix_trace_flush()
function. The trace system shall restart the trace stream
when it is empty and may restart it sooner. A
POSIX_TRACE_START trace event shall be reported before
reporting the next recorded trace event.
POSIX_TRACE_FLUSH
If the Trace Log option is supported, this policy is
identical to the POSIX_TRACE_UNTIL_FULL trace stream full
policy except that the trace stream shall be flushed
regularly as if posix_trace_flush() had been explicitly
called. Defining this policy for an active trace stream
without log shall be invalid.
The default value for the stream-full-policy attribute shall be
POSIX_TRACE_LOOP for an active trace stream without log.
If the Trace Log option is supported, the default value for the
stream-full-policy attribute shall be POSIX_TRACE_FLUSH for an
active trace stream with log.
Возвращаемое значение (Return value)
Upon successful completion, these functions shall return a value
of zero. Otherwise, they shall return the corresponding error
number.
If successful, the posix_trace_attr_getinherited() function shall
store the inheritance attribute value in the object pointed to by
inheritancepolicy. Otherwise, the content of this object is
undefined.
If successful, the posix_trace_attr_getlogfullpolicy() function
shall store the log-full-policy attribute value in the object
pointed to by logpolicy. Otherwise, the content of this object
is undefined.
If successful, the posix_trace_attr_getstreamfullpolicy()
function shall store the stream-full-policy attribute value in
the object pointed to by streampolicy. Otherwise, the content of
this object is undefined.
Ошибки (Error)
These functions may fail if:
EINVAL The value specified by at least one of the arguments is
invalid.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
The following functions:
posix_trace_attr_getinherited()
posix_trace_attr_getlogfullpolicy()
posix_trace_attr_getstreamfullpolicy()
posix_trace_attr_setinherited()
posix_trace_attr_setlogfullpolicy()
posix_trace_attr_setstreamfullpolicy()
may be removed in a future version.
Смотри также (See also)
fork(3p), posix_trace_attr_destroy(3p), posix_trace_create(3p),
posix_trace_get_attr(3p), posix_trace_getnext_event(3p),
posix_trace_start(3p)
The Base Definitions volume of POSIX.1‐2017, trace.h(0p)
