pthread_getthrds_np() Subroutine

Base Operating System and Extensions Technical Reference, Volume 1

pthread_getthrds_np() Subroutine

Purpose

Retrieves register and stack information for threads.

Library

Threads Library (libpthreads.a)

Syntax

#include <pthread.h>

pthread_getthrds_np (pthread_t *thread, int mode,
                    struct __pthrdsinfo *buf, int bufsize,
                    void *regbuf, int *regbufsize);

Description

The pthread_getthrds_np subroutine retrieves information on the state of the thread thread and its underlying kernel thread, including register and stack information.

Parameters

thread

The pointer to the thread. On input it identifies the target thread of the operation, or 0 to operate on the first entry in the list of threads. On output it identifies the next entry in the list of threads, or 0 if the end of the list has been reached. pthread_getthrds_np can be used to traverse the whole list of threads by starting with thread pointing to 0 and calling pthread_getthrds_np repeatedly until it returns with thread pointing to 0.

mode

Specifies the type of query. These values can be bitwise or'ed together to specify more than one type of query.

PTHRDSINFO_QUERY_GPRS	get general purpose registers
PTHRDSINFO_QUERY_SPRS	get special purpose registers
PTHRDSINFO_QUERY_FPRS	get floating point registers
PTHRDSINFO_QUERY_REGS	get all of the above registers
PTHRDSINFO_QUERY_TID	get the kernel thread id
PTHRDSINFO_QUERY_ALL	get everything

buf

Specifies the address of the struct __pthrdsinfo structure that will be filled in by pthread_getthrds_np. On return, this structure holds the following data (depending on the type of query requested):

__pi_ptid

The thread's thread identifier

__pi_tid

The thread's kernel thread id, or 0 if the thread does not have a kernel thread

__pi_state

The state of the thread, equal to one of the following:

PTHRDSINFO_STATE_RUN	The thread is running
PTHRDSINFO_STATE_READY	The thread is ready to run
PTHRDSINFO_STATE_IDLE	The thread is being initialized
PTHRDSINFO_STATE_SLEEP	The thread is sleeping
PTHRDSINFO_STATE_TERM	The thread is terminated
PTHRDSINFO_STATE_NOTSUP	Error condition

__pi_suspended

1 if the thread is suspended, 0 if it is not

__pi_returned

The return status of the thread

__pi_ustk

The thread's user stack pointer

__pi_context

The thread's context (register information)

bufsize

The size of the __pthrdsinfo structure in bytes.

regbuf

The location of the buffer to hold the register save data from the kernel if the thread is in a system call.

regbufsize

The pointer to the size of the regbuf buffer. On input, it identifies the maximum size of the buffer in bytes. On output, it identifies the number of bytes of register save data. If the thread is not in a system call, there is no register save data returned from the kernel, and regbufsize is 0. If the size of the register save data is larger than the input value of regbufsize, the number of bytes specified by the input value of regbufsize is copied to regbuf, pthread_getthrds_np() returns ERANGE, and the output value of regbufsize specifies the number of bytes required to hold all of the register save data.

Return Values

If successful, the pthread_getthrds_np function returns zero. Otherwise, an error number is returned to indicate the error.

Error Codes

The pthread_getthrds_np function will fail if:

EINVAL	Either thread or buf is NULL, or bufsize is not equal to the size of the __pthrdsinfo structure in the library.
ESRCH	No thread could be found corresponding to that specified by the thread ID thread.
ERANGE	regbuf was not large enough to handle all of the register save data.
ENOMEM	Insufficient memory exists to perform this operation.

Implementation Specifics

This subroutine is part of the Base Operating System (BOS) Runtime.

Related Information

The pthread.h file.