Signal之基本知识

Taishan3721

发布于 2020-06-23 16:22:10

1.3K0

发布于 2020-06-23 16:22:10

Signal是一种处理异常或异步改变执行流程的机制，类似于软中断。与POSIX兼容，VxWorks也定义了63种Signal(0为NULL Signal)


#define SIGHUP     1 /* hangup */
#define SIGINT     2 /* interrupt */
#define SIGQUIT    3 /* quit */
#define SIGILL     4 /* illegal instruction (not reset when caught) */
#define SIGTRAP    5 /* trace trap (not reset when caught) */
#define SIGABRT    6 /* used by abort, replace SIGIOT in the future */
#define SIGEMT     7 /* EMT instruction */
#define SIGFPE     8 /* floating point exception */
#define SIGKILL    9 /* kill */
#define SIGBUS    10 /* bus error */
#define SIGSEGV   11 /* segmentation violation */
#define SIGFMT    12 /* STACK FORMAT ERROR (not posix) */
#define SIGPIPE   13 /* write on a pipe with no one to read it */
#define SIGALRM   14 /* alarm clock */
#define SIGTERM   15 /* software termination signal from kill */
#define SIGCNCL   16 /* pthreads cancellation signal */
#define SIGSTOP   17 /* sendable stop signal not from tty */
#define SIGTSTP   18 /* stop signal from tty */
#define SIGCONT   19 /* continue a stopped process */
#define SIGCHLD   20 /* to parent on child stop or exit */
#define SIGTTIN   21 /* to readers pgrp upon background tty read */
#define SIGTTOU   22 /* like TTIN for output if (tp->t_local&LTOSTOP) */

#define SIGRES1   23 /* reserved signal number (Not POSIX) */
#define SIGRES2   24 /* reserved signal number (Not POSIX) */
#define SIGRES3   25 /* reserved signal number (Not POSIX) */
#define SIGRES4   26 /* reserved signal number (Not POSIX) */
#define SIGRES5   27 /* reserved signal number (Not POSIX) */
#define SIGRES6   28 /* reserved signal number (Not POSIX) */
#define SIGRES7   29 /* reserved signal number (Not POSIX) */

#define SIGUSR1   30 /* user defined signal 1 */
#define SIGUSR2   31 /* user defined signal 2 */

#define SIGPOLL   32 /* pollable event */
#define SIGPROF   33 /* profiling timer expired */
#define SIGSYS    34 /* bad system call */
#define SIGURG    35 /* high bandwidth data is available at socket */
#define SIGVTALRM 36 /* virtual timer expired */
#define SIGXCPU   37 /* CPU time limit exceeded */
#define SIGXFSZ   38 /* file size time limit exceeded */

#define SIGEVTS   39 /* signal event thread send */
#define SIGEVTD   40 /* signal event thread delete */

#define SIGRTMIN  48 /* Realtime signal min */
#define SIGRTMAX  63 /* Realtime signal max */

#define _NSIGS    63

任务或ISR可以发送Signal到任务本身或其它任务；而对方可以根据Signal Mask选择接收还是忽略该Signal。如果要接收的话，需要注册Signal的处理函数

发送Signal时，使用的是发送者的上下文。而处理函数在处理接收到的Signal时，使用的是接收者的上下文。即使接收者阻塞或者挂起了，这个处理还是会执行的。

Signal的处理函数中可以调用的系统函数有这些

库	函数
bLib	All routines
errnoLib	errnoGet(), errnoSet()
eventLib	eventSend()
fppArchLib	fppSave(), fppRestore()
intLib	intContext(), intCount(), intVecSet(), intVecGet()
intArchLib	intLock(), intUnlock()
logLib	logMsg()
lstLib	All routines except lstFree()
mathALib	All routines, if fppSave()/fppRestore() are used
msgQLib	msgQSend()
rngLib	All routines except rngCreate() and rngDelete()
semLib	semGive() except mutual-exclusion semaphores, semFlush()
sigLib	kill()
taskLib	taskSuspend(), taskResume(), taskPrioritySet(), taskPriorityGet(), taskIdVerify(), taskIdDefault(), taskIsReady(), taskIsSuspended(), taskIsPended(), taskIsDelayed(), taskTcb()
tickLib	tickAnnounce(), tickSet(), tickGet()
tyLib	tyIRd(), tyITx()
vxLib	vxTas(), vxMemProbe()
wdLib	wdStart(), wdCancel()
spinLockLib	spinLockIsrTake() and spinLockIsrGive()
vxAtomicLib	All routines.
vxCpuLib	vxCpuIndexGet(), vxCpuIdGet(), vxCpuPhysIndexGet(), vxCpuIdToPhysIndex(), vxCpuPhysIndexToId(), vxCpuReservedGet(), CPU_LOGICAL_TO_PHYS(), and CPU_PHYS_TO_LOGICAL()
fioLib	vsprintf() and vsnprintf()
fioBaseLib	sprintf() and snprintf()
ansiString	All routines.