Originální popis anglicky:
posix_trace_create, posix_trace_create_withlog, posix_trace_flush,
posix_trace_shutdown - trace stream initialization, flush, and shutdown from a
process (
TRACING)
Návod, kniha: POSIX Programmer's Manual
#include <sys/types.h>
#include <trace.h>
int posix_trace_create(pid_t
pid,
const trace_attr_t *restrict
attr,
trace_id_t *restrict
trid);
int posix_trace_create_withlog(pid_t pid,
const trace_attr_t *restrict
attr, int
file_desc,
trace_id_t *restrict
trid);
int posix_trace_flush(trace_id_t
trid);
int posix_trace_shutdown(trace_id_t trid);
The
posix_trace_create() function shall create an active trace stream. It
allocates all the resources needed by the trace stream being created for
tracing the process specified by
pid in accordance with the
attr
argument. The
attr argument represents the initial attributes of the
trace stream and shall have been initialized by the function
posix_trace_attr_init() prior to the
posix_trace_create() call.
If the argument
attr is NULL, the default attributes shall be used. The
attr attributes object shall be manipulated through a set of functions
described in the
posix_trace_attr family of functions. If the
attributes of the object pointed to by
attr are modified later, the
attributes of the trace stream shall not be affected. The
creation-time
attribute of the newly created trace stream shall be set to the value of the
system clock, if the Timers option is not supported, or to the value of the
CLOCK_REALTIME clock, if the Timers option is supported.
The
pid argument represents the target process to be traced. If the
process executing this function does not have appropriate privileges to trace
the process identified by
pid, an error shall be returned. If the
pid argument is zero, the calling process shall be traced.
The
posix_trace_create() function shall store the trace stream identifier
of the new trace stream in the object pointed to by the
trid argument.
This trace stream identifier shall be used in subsequent calls to control
tracing. The
trid argument may only be used by the following functions:
| posix_trace_clear() posix_trace_eventid_equal()
posix_trace_eventid_get_name()
posix_trace_eventtypelist_getnext_id()
posix_trace_eventtypelist_rewind() posix_trace_get_attr()
posix_trace_get_status() |
posix_trace_getnext_event() posix_trace_shutdown()
posix_trace_start() posix_trace_stop()
posix_trace_timedgetnext_event()
posix_trace_trid_eventid_open()
posix_trace_trygetnext_event() |
If the Trace Event Filter option is supported, the following additional
functions may use the
trid argument:
| posix_trace_get_filter() |
posix_trace_set_filter() |
In particular, notice that the operations normally used by a trace analyzer
process, such as
posix_trace_rewind() or
posix_trace_close(),
cannot be invoked using the trace stream identifier returned by the
posix_trace_create() function.
A trace stream shall be created in a suspended state. If the Trace Event
Filter option is supported, its trace event type filter shall be empty.
The
posix_trace_create() function may be called multiple times from the
same or different processes, with the system-wide limit indicated by the
runtime invariant value {TRACE_SYS_MAX}, which has the minimum value
{_POSIX_TRACE_SYS_MAX}.
The trace stream identifier returned by the
posix_trace_create() function
in the argument pointed to by
trid is valid only in the process that
made the function call. If it is used from another process, that is a child
process, in functions defined in IEEE Std 1003.1-2001, these
functions shall return with the error [EINVAL].
The
posix_trace_create_withlog() function shall be equivalent to
posix_trace_create(), except that it associates a trace log with this
stream. The
file_desc argument shall be the file descriptor designating
the trace log destination. The function shall fail if this file descriptor
refers to a file with a file type that is not compatible with the log policy
associated with the trace log. The list of the appropriate file types that are
compatible with each log policy is implementation-defined.
The
posix_trace_create_withlog() function shall return in the parameter
pointed to by
trid the trace stream identifier, which uniquely
identifies the newly created trace stream, and shall be used in subsequent
calls to control tracing. The
trid argument may only be used by the
following functions:
| posix_trace_clear() posix_trace_eventid_equal()
posix_trace_eventid_get_name()
posix_trace_eventtypelist_getnext_id()
posix_trace_eventtypelist_rewind() posix_trace_flush()
posix_trace_get_attr() posix_trace_get_status()
|
posix_trace_getnext_event() posix_trace_shutdown()
posix_trace_start() posix_trace_stop()
posix_trace_timedgetnext_event()
posix_trace_trid_eventid_open()
posix_trace_trygetnext_event() |
If the Trace Event Filter option is supported, the following additional
functions may use the
trid argument:
| posix_trace_get_filter() |
posix_trace_set_filter() |
In particular, notice that the operations normally used by a trace analyzer
process, such as
posix_trace_rewind() or
posix_trace_close(),
cannot be invoked using the trace stream identifier returned by the
posix_trace_create_withlog() function.
The
posix_trace_flush() function shall initiate a flush operation which
copies the contents of the trace stream identified by the argument
trid
into the trace log associated with the trace stream at the creation time. If
no trace log has been associated with the trace stream pointed to by
trid, this function shall return an error. The termination of the flush
operation can be polled by the
posix_trace_get_status() function.
During the flush operation, it shall be possible to trace new trace events up
to the point when the trace stream becomes full. After flushing is completed,
the space used by the flushed trace events shall be available for tracing new
trace events.
If flushing the trace stream causes the resulting trace log to become full, the
trace log full policy shall be applied. If the trace
log-full-policy
attribute is set, the following occurs:
- POSIX_TRACE_UNTIL_FULL
-
The trace events that have not yet been flushed shall be discarded.
- POSIX_TRACE_LOOP
-
The trace events that have not yet been flushed shall be written to the
beginning of the trace log, overwriting previous trace events stored
there.
- POSIX_TRACE_APPEND
-
The trace events that have not yet been flushed shall be appended to the
trace log.
The
posix_trace_shutdown() function shall stop the tracing of trace
events in the trace stream identified by
trid, as if
posix_trace_stop() had been invoked. The
posix_trace_shutdown()
function shall free all the resources associated with the trace stream.
The
posix_trace_shutdown() function shall not return until all the
resources associated with the trace stream have been freed. When the
posix_trace_shutdown() function returns, the
trid argument
becomes an invalid trace stream identifier. A call to this function shall
unconditionally deallocate the resources regardless of whether all trace
events have been retrieved by the analyzer process. Any thread blocked on one
of the
trace_getnext_event() functions (which specified this
trid) before this call is unblocked with the error [EINVAL].
If the process exits, invokes a member of the
exec family of functions,
or is terminated, the trace streams that the process had created and that have
not yet been shut down, shall be automatically shut down as if an explicit
call were made to the
posix_trace_shutdown() function.
For an active trace stream with log, when the
posix_trace_shutdown()
function is called, all trace events that have not yet been flushed to the
trace log shall be flushed, as in the
posix_trace_flush() function, and
the trace log shall be closed.
When a trace log is closed, all the information that may be retrieved later from
the trace log through the trace interface shall have been written to the trace
log. This information includes the trace attributes, the list of trace event
types (with the mapping between trace event names and trace event type
identifiers), and the trace status.
In addition, unspecified information shall be written to the trace log to allow
detection of a valid trace log during the
posix_trace_open() operation.
The
posix_trace_shutdown() function shall not return until all trace
events have been flushed.
Upon successful completion, these functions shall return a value of zero.
Otherwise, they shall return the corresponding error number.
The
posix_trace_create() and
posix_trace_create_withlog()
functions store the trace stream identifier value in the object
pointed to by
trid, if successful.
The
posix_trace_create() and
posix_trace_create_withlog()
functions shall fail if:
- EAGAIN
- No more trace streams can be started now. {TRACE_SYS_MAX}
has been exceeded.
- EINTR
- The operation was interrupted by a signal. No trace stream
was created.
- EINVAL
- One or more of the trace parameters specified by the
attr parameter is invalid.
- ENOMEM
- The implementation does not currently have sufficient
memory to create the trace stream with the specified parameters.
- EPERM
- The caller does not have appropriate privilege to trace the
process specified by pid.
- ESRCH
- The pid argument does not refer to an existing
process.
The
posix_trace_create_withlog() function shall fail if:
- EBADF
- The file_desc argument is not a valid file
descriptor open for writing.
- EINVAL
- The file_desc argument refers to a file with a file
type that does not support the log policy associated with the trace
log.
- ENOSPC
- No space left on device. The device corresponding to the
argument file_desc does not contain the space required to create
this trace log.
The
posix_trace_flush() and
posix_trace_shutdown()
functions shall fail if:
- EINVAL
- The value of the trid argument does not correspond
to an active trace stream with log.
- EFBIG
- The trace log file has attempted to exceed an
implementation-defined maximum file size.
- ENOSPC
- No space left on device.
The following sections are informative.
None.
None.
None.
None.
clock_getres() ,
exec() ,
posix_trace_attr_init() ,
posix_trace_clear() ,
posix_trace_close() ,
posix_trace_eventid_equal() ,
posix_trace_eventtypelist_getnext_id() ,
posix_trace_flush() ,
posix_trace_get_attr() ,
posix_trace_get_filter() ,
posix_trace_get_status() ,
posix_trace_getnext_event() ,
posix_trace_open() ,
posix_trace_set_filter() ,
posix_trace_shutdown() ,
posix_trace_start() ,
posix_trace_timedgetnext_event() ,
posix_trace_trid_eventid_open() ,
posix_trace_start() ,
time() , the Base Definitions volume of
IEEE Std 1003.1-2001,
<sys/types.h>,
<trace.h>
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
.
