bt_init_accessor()

Initialize a backtrace accessor

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The backtrace library is an unsupported feature, due to its fragility. For more information, see Backtraces in the QNX Neutrino technotes.

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Synopsis:

#include <backtrace.h>

int bt_init_accessor( bt_accessor_t *acc,
                      bt_acc_type_t type, ...);

Arguments:

acc

A pointer to a bt_accessor_t structure. This is an opaque structure that holds the identity of the thread to backtrace.

type

The type of backtrace to perform; one of:

• BT_SELF — backtrace the calling thread.
• BT_THREAD — backtrace a specified thread in the current process.
• BT_PROCESS — backtrace a specified thread in another process.

Additional arguments are required for BT_THREAD and BT_PROCESS, as described below.

Library:

libbacktrace

Use the -l backtrace option to qcc to link against this library.

Description:

The bt_init_accessor() function initializes the accessor with the identity of the thread to backtrace:

• To backtrace the calling thread, use:

  bt_init_accessor(bt_accessor_t *acc, BT_SELF);
    

• To backtrace a thread in the current process, use:

  bt_init_accessor(bt_accessor_t *acc, BT_THREAD, pthread_t tid);
    

• To backtrace a thread in any process, use:

  bt_init_accessor(bt_accessor_t *acc, BT_PROCESS, pid_t pid, pthread_t tid)
    

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The bt_acc_self global variable is a preinitialized accessor used to backtrace the current thread. Don't call bt_init_accessor() or bt_release_accessor() for this variable.

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Returns:

0

Success.

-1

An error occurred (errno is set).

Errors:

EINVAL

The acc argument is NULL, or the type is invalid.

Classification:

QNX Neutrino

See also:

bt_get_backtrace(), bt_load_memmap(), bt_release_accessor(), bt_set_flags(), bt_sprn_memmap(), bt_sprnf_addrs(), bt_translate_addrs(), bt_unload_memmap()

Backtraces in the QNX Neutrino technotes

pidin backtrace in the Utilities Reference