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% PT_EVT_ALLOC_DECODER(3)
<!---
! Copyright (c) 2015-2025, Intel Corporation
! SPDX-License-Identifier: BSD-3-Clause
!
! Redistribution and use in source and binary forms, with or without
! modification, are permitted provided that the following conditions are met:
!
! * Redistributions of source code must retain the above copyright notice,
! this list of conditions and the following disclaimer.
! * Redistributions in binary form must reproduce the above copyright notice,
! this list of conditions and the following disclaimer in the documentation
! and/or other materials provided with the distribution.
! * Neither the name of Intel Corporation nor the names of its contributors
! may be used to endorse or promote products derived from this software
! without specific prior written permission.
!
! THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
! AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
! IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
! ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
! LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
! CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
! SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
! INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
! CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
! ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
! POSSIBILITY OF SUCH DAMAGE.
!-->
# NAME
pt_evt_alloc_decoder, pt_evt_free_decoder - allocate/free an Intel(R) Processor
Trace event decoder
# SYNOPSIS
| **\#include `<intel-pt.h>`**
|
| **struct pt_event_decoder \***
| **pt_evt_alloc_decoder(const struct pt_config \**config*);**
|
| **void pt_evt_free_decoder(struct pt_event_decoder \**decoder*);**
Link with *-lipt*.
# DESCRIPTION
A event decoder decodes raw Intel Processor Trace (Intel PT) and combines Intel
PT packets into a stream of Intel PT events.
This information can be used to reconstruct the execution flow of the traced
code. Decode instructions until the next event, then apply the event.
**pt_evt_alloc_decoder**() allocates a new event decoder and returns a pointer
to it. The *config* argument points to a *pt_config* object. See
**pt_config**(3). The *config* argument will not be referenced by the returned
decoder but the trace buffer defined by the *config* argument's *begin* and
*end* fields will.
The returned event decoder needs to be synchronized onto the trace stream before
it can be used. To synchronize the event decoder, use
**pt_evt_sync_forward**(3), **pt_evt_sync_backward**(3), or
**pt_evt_sync_set**(3).
**pt_evt_free_decoder**() frees the Intel PT event decoder pointed to by
*decoder*. The *decoder* argument must be NULL or point to a decoder that has
been allocated by a call to **pt_evt_alloc_decoder**().
# RETURN VALUE
**pt_evt_alloc_decoder**() returns a pointer to a *pt_event_decoder* object on
success or NULL in case of an error.
# EXAMPLE
~~~{.c}
int foo(const struct pt_config *config) {
struct pt_event_decoder *decoder;
errcode;
decoder = pt_evt_alloc_decoder(config);
if (!decoder)
return -pte_nomem;
errcode = bar(decoder);
pt_evt_free_decoder(decoder);
return errcode;
}
~~~
# SEE ALSO
**pt_config**(3), **pt_evt_sync_forward**(3), **pt_evt_sync_backward**(3),
**pt_evt_sync_set**(3), **pt_evt_get_offset**(3), **pt_evt_get_sync_offset**(3),
**pt_evt_get_config**(3), **pt_evt_next**(3)
|
