/*****************************************************************************
Copyright (c) 1995, 2011, Oracle and/or its affiliates. All Rights Reserved.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
*****************************************************************************/
/**************************************************//**
@file include/os0thread.h
The interface to the operating system
process and thread control primitives
Created 9/8/1995 Heikki Tuuri
*******************************************************/
#ifndef os0thread_h
#define os0thread_h
#include "univ.i"
#ifdef UNIV_LINUX
#include <sys/types.h>
#endif
/* Maximum number of threads which can be created in the program;
this is also the size of the wait slot array for MySQL threads which
can wait inside InnoDB */
#define OS_THREAD_MAX_N srv_max_n_threads
/* Possible fixed priorities for threads */
#define OS_THREAD_PRIORITY_NONE 100
#define OS_THREAD_PRIORITY_BACKGROUND 1
#define OS_THREAD_PRIORITY_NORMAL 2
#define OS_THREAD_PRIORITY_ABOVE_NORMAL 3
#ifdef __WIN__
typedef void* os_thread_t;
typedef DWORD os_thread_id_t; /*!< In Windows the thread id
is an unsigned long int */
typedef os_thread_id_t os_tid_t;
extern "C" {
typedef LPTHREAD_START_ROUTINE os_thread_func_t;
}
/** Macro for specifying a Windows thread start function. */
#define DECLARE_THREAD(func) WINAPI func
/** Required to get around a build error on Windows. Even though our functions
are defined/declared as WINAPI f(LPVOID a); the compiler complains that they
are defined as: os_thread_ret_t (__cdecl*)(void*). Because our functions
don't access the arguments and don't return any value, we should be safe. */
#define os_thread_create(f,a,i) \
os_thread_create_func(reinterpret_cast<os_thread_func_t>(f), a, i)
#else
typedef pthread_t os_thread_t;
typedef os_thread_t os_thread_id_t; /*!< In Unix we use the thread
handle itself as the id of
the thread */
#ifdef UNIV_LINUX
typedef pid_t os_tid_t; /*!< An alias for pid_t on
Linux, where setpriority()
accepts thread id of this type
and not pthread_t */
#else
typedef os_thread_id_t os_tid_t;
#endif
extern "C" { typedef void* (*os_thread_func_t)(void*); }
/** Macro for specifying a POSIX thread start function. */
#define DECLARE_THREAD(func) func
#define os_thread_create(f,a,i) os_thread_create_func(f, a, i)
#endif /* __WIN__ */
/* Define a function pointer type to use in a typecast */
typedef void* (*os_posix_f_t) (void*);
#ifdef HAVE_PSI_INTERFACE
/* Define for performance schema registration key */
typedef unsigned int mysql_pfs_key_t;
#endif
/***************************************************************//**
Compares two thread ids for equality.
@return TRUE if equal */
UNIV_INTERN
ibool
os_thread_eq(
/*=========*/
os_thread_id_t a, /*!< in: OS thread or thread id */
os_thread_id_t b); /*!< in: OS thread or thread id */
/****************************************************************//**
Converts an OS thread id to a ulint. It is NOT guaranteed that the ulint is
unique for the thread though!
@return thread identifier as a number */
UNIV_INTERN
ulint
os_thread_pf(
/*=========*/
os_thread_id_t a); /*!< in: OS thread identifier */
/****************************************************************//**
Creates a new thread of execution. The execution starts from
the function given. The start function takes a void* parameter
and returns a ulint.
NOTE: We count the number of threads in os_thread_exit(). A created
thread should always use that to exit and not use return() to exit.
@return handle to the thread */
UNIV_INTERN
os_thread_t
os_thread_create_func(
/*==================*/
os_thread_func_t func, /*!< in: pointer to function
from which to start */
void* arg, /*!< in: argument to start
function */
os_thread_id_t* thread_id); /*!< out: id of the created
thread, or NULL */
/*****************************************************************//**
Exits the current thread. */
UNIV_INTERN
void
os_thread_exit(
/*===========*/
void* exit_value) /*!< in: exit value; in Windows this void*
is cast as a DWORD */
UNIV_COLD __attribute__((noreturn));
/*****************************************************************//**
Returns the thread identifier of current thread.
@return current thread identifier */
UNIV_INTERN
os_thread_id_t
os_thread_get_curr_id(void);
/*========================*/
/*****************************************************************//**
Returns the system-specific thread identifier of current thread. On Linux,
returns tid. On other systems currently returns os_thread_get_curr_id().
@return current thread identifier */
UNIV_INTERN
os_tid_t
os_thread_get_tid(void);
/*=====================*/
/*****************************************************************//**
Advises the os to give up remainder of the thread's time slice. */
UNIV_INTERN
void
os_thread_yield(void);
/*=================*/
/*****************************************************************//**
The thread sleeps at least the time given in microseconds. */
UNIV_INTERN
void
os_thread_sleep(
/*============*/
ulint tm); /*!< in: time in microseconds */
/*****************************************************************//**
Set relative scheduling priority for a given thread on Linux. Currently a
no-op on other systems.
@return An actual thread priority after the update */
UNIV_INTERN
ulint
os_thread_set_priority(
/*===================*/
os_tid_t thread_id, /*!< in: thread id */
ulint relative_priority); /*!< in: system-specific
priority value */
#ifndef UNIV_NONINL
#include "os0thread.ic"
#endif
#endif