| Linearg posted on 11:34:00 |
1. Official Program Guide
In the installation directory:/docs/VxWorks/GUIDE/index.html Ii. Common databases:
# I nclude "tasklib. H"/* task */
# I nclude "msgqlib. H"/* Message Queue */
# I nclude "semlib. H"/* semaphore */
# I nclude "iolib. H"/* IO */
# I nclude "wdlib. H"/* Watch Dog */
# I nclude "loglib. H"/* information output */
# I nclude "socket. H"/* network socket */ Iii. Io system: iolib. h
1. the I/O devices in the system, including the keyboard, serial port, and files, are accessed using unified interfaces. The first step is to get the file descriptor first, then read/write or set, and finally close the descriptor.
Creat: create a file
Open: get the file or device descriptor
Read: reads files or devices.
Write: Write a file or device
IOCTL: set parameters
Close: Close file descriptor
Remove: delete an object 2. memory files
Memdrv ()-initialize a pseudo-memory device
Memdevcreate ()-create a pseudo-memory device
Memdevcreatedir ()-creates a set of pseudo-memory devices
Memdevdelete ()-delete a pseudo-memory device Init (){
Uchar_t buffer [1024];
Int FD;
Memdrv ();
Memdevcreate ("/MEM/mem1", buffer, sizeof (buffer ));
If (FD = open ("/MEM/mem1", o_rdwr, 0644 ))! = Error ){
Write (FD, & Data, sizeof (data ));
......
Close (FD );
}
Memdevdelete ("/MEM/mem1 ");
} 3. implement multiple Io listeners using the select function: selectlib. h
When waiting for multiple Io, we can use the select function. FD is the file descriptor:
Int select (
Int width,/* The maximum FD, or fd_setsize (2048 )*/
Fd_set * preadfds,/* read FD Set */
Fd_set * pwritefds,/* FD set written */
Fd_set * p1_tfds,/* not supported by VxWorks, null */
Struct timeval * ptimeout/* wait time, null = forever */
)
There are several macros:
Fd_set (FD, & fdset) sets the listening bit of FD
Fd_clr (FD, & fdset) clears the listening bit of FD
Fd_zero (& fdset) clears all listening bits
Fd_isset (FD, & fdset) Whether FD has data
For example, Max indicates the maximum value:
Init (){
Struct fd_set readfds;
Int FDS [4];
Int width; FDS [0] = open (...); ......; FDS [3] = open (...);/* Open Io */
Width = max (FDS [0],..., FDS [3]) + 1;/* maximum FD value + 1 */
/* Forever {*/
Fd_zero (& readfds);/* set the fd_set structure */
Fd_set (FDS [0], & readfds); ......; fd_set (FDS [3], & readfds ); If (select (width, & readfds, null) = Error) {/* listener */
Close (FDS [0]); ...... close (FDS [3]);
Return;
}
For (I = 0; I
If (fd_isset (FDS [I], & readfds )){
...;/* Perform read/write operations */
}
}
/*}*/
} 4. Multi-task environment programming:
1. Task Control: tasklib. h
Taskspawn ()-create a task
Taskinit ()-initialize the task. You can specify the stack and PCB address by yourself.
Taskactivate ()-activate an initialized task
Exit ()-end in task (ANSI)
Taskdelete ()-delete a task
Taskdeleteforce ()-force Delete, even if it is protected
Tasksuspend ()-pending a task
Taskresume ()-resume a pending task
Taskrestart ()-restart a task
Taskpriorityset ()-change the task priority
Taskpriorityget ()-read task priority
Tasklock ()-Disable Task Scheduling
Taskunlock ()-allows Task Scheduling
Tasksafe ()-protect tasks from being deleted
Taskunsafe ()-unprotect
Taskdelay ()-latency
Taskidself ()-Get the ID of the current task
Taskidverify ()-whether the task id exists
Tasktcb ()-Get the address of the task control block (TCB)
Taskoptionsset ()-Change Task options
Taskoptionsget ()-Get the current task Option
Taskregsget ()-obtain the register information in task TCB.
Taskregsset ()-set register information in task TCB
Taskname ()-Get the Task Name
Tasknametoid ()-ID obtained by name
Taskiddefault ()-set the default task id
Taskisready ()-whether the task is ready
Taskissuincluded ()-whether the task is suspended
Taskidlistget ()-Get the list of active tasks 2. Task mutex-semaphores: semlib. h
Semgive ()-release a semaphore
Semtake ()-getting a semaphore will block
Semflush ()-changes all tasks blocked on this semaphore to ready state
Semdelete ()-delete a semaphore
1) binary semaphore: sembcreate
It can be used for task synchronization and mutex, but is often used for task synchronization.
2) mutex semaphores: semmcreate
Semaphores dedicated to task mutex to protect critical resources
3) Count semaphores: semccreate
Multi-instance Resource Access Control 3. task synchronization
1) Message Queue: msgqlib. h
Message Queue
Msgqcreate ()-create a message queue
Msgqdelete ()-delete a Message Queue
Msgqsend ()-send messages
Msgqreceive ()-receives messages and blocks messages after the call
Msgqnummsgs ()-Get the number of messages in the Message Queue Init (){
/* Create A Message Queue */
If (msgqid = msgqcreate (8, 1, msg_q_fifo) = NULL ){
Printf ("Message Queue create failed! /N ");
}
} Tasksend (){
If (OK! = Msgqsend (msgqid, "A", 1, no_wait, msg_pri_normal )){
Printf ("Message send failed! ");
}
} Taskreceive (){
Uchar_t ch;
Msgqreceive (msgqid, & Ch, 1, wait_forever);/* the task will be blocked */
Printf ("received from msgq: % C", CH );
} 2) pipe: iolib. h. The system includes the pipe driver by default.
Pipedevcreate ()-create an MPS queue
Pipedevdelete ()-delete MPs queue
Because the pipeline is Io, you can use select listeners. Message Queues are not Io and cannot use select Init (){
/* Create an MPS queue */
If (pipedevcreate ("/pipe/mypipe", 8, 1 )! = OK ){
Printf ("/pipe/mypipe create fialed! /N ");
}
/* Create mutex semaphores */
If (semmid = semmcreate (sem_q_fifo) = NULL)
{
Printf ("mutex semaphore create failed! /N ");
}
} Tasksend (){
Int PD;/* pipe descriptor */
If (Pd = open ("/pipe/mypipe", o_wronly, 0644) = Error ){
Printf ("Open pipe failed! ");
}
If (semtake (semmid, no_wait) = Error ){
Printf ("pipe in use! ");
}
Write (PD, "A", 1 );
Semgive (semmid );
Close (PD );
} Taskreceive (){
Int PD;/* pipe descriptor */
Uchar_t ch;
If (Pd = open ("/pipe/mypipe", o_rdonly, 0644) = Error ){
Printf ("Open pipe failed! ");
}
If (read (PD, & Ch, 1)> 0) {/* the task will be blocked */
Printf ("received from pipe: % C", CH );
}
} 3) binary semaphores
Init (){
/* Create a binary semaphore */
If (sembid = sembcreate (sem_q_fifo, sem_empty) = NULL ){
Printf ("binary semaphore create failed! /N ");
}
} Tasksend (){
Semgive (sembid );
} Taskreceive (){
Semtake (sembid, wait_forever);/* the task will be blocked */
} 4) Event: eventlib
The ID of the target task to be specified when an event is sent
Eventreceive ()-Wait for event
Eventsend ()-send events
Eventclear ()-Clear the event of the current task. Tasksend (){
If (OK! = Eventsend (taskreceiveid, 0x00000001 )){
Printf ("event send failed! ");
}
} Taskreceive (){
Uint32 EV;
If (OK! = Eventreceive (0x00ffffff, events_wait_any, wait_forever, & eV )){
Printf ("eventreceive error! /N ");
}
Else {
Ev & = 0x00000001;
If (EV ){
Printf ("event % d received! ", Ev );
}
}
} 5. Watch Dog: wdlib. h
The system provides a soft watchdog timer, which is easy to use:
Wdcreate ()-create a watchdog
Wddelete ()-delete
Wdstart ()-start
Wdcancel ()-Stop Init (){
/* Create a watchdog */
If (wdid = wdcreate () = NULL ){
Printf ("Watch Dog create failed! /N ");
}
} Task (){
If (OK! = Wdstart (wdid, sysclkrateget () * 5, proc_wd, 0 )){
Printf ("Watch Dog start failed! /N ");
}
} Int proc_wd (int param ){
Logmsg (......);
} 6. Network Programming: socklib. h
Use a standard BSD socket and TCP or UDP for communication.
Socket ()-open socket
BIND ()-bind to port and address
Listen ()-listener Mode
Accept ()-allow the connection of the other party
Connect ()-active remote connection
Connectwithtimeout ()-connect function of the timeout Function
Sendto ()-send
Send ()-send
Sendmsg ()-send
Recvfrom ()-receive
Recv ()-receive
Recvmsg ()-receive
Setsockopt ()-set socket Parameters
Getsockopt ()-obtain the socket Parameter
Getsockname ()-obtain the socket name
Getpeername ()-Get the name of the connected point
Shutdown ()-close connection VII. Exception Handling
1. Error code: errnolib. h
32-bit signed integer, 1 ~ 500 occupied by the system and available in other programs. For example
# Define memory_leak 0x20005
Errnoget ()-Get the error code of the current task
Errnooftaskget ()-Get the error code of the specified task
Errnoset ()-set the error number of the current task
Errnooftaskset ()-set the error number of the specified task 2. Signal: siglib. h
Signal ()-entry function of the specified signal
Raise ()-send a signal to the current task
Kill ()-send a signal to a specified task Task1 (){
Signal (30, proc_sig);/* sign up for the 30th signal */
/* Raise (30 );*/
} Task2 (){
Kill (task1id, 30 );
} Void proc_sig (int param ){
Logmsg ("error message ...");
} VIII. Interruption: IV. H
0x0 ~ of x86 ~ 0xf: The value 0x20 ~ in VxWorks ~ 0x2f interrupted
Take interruption on the 9th as an example:
Initialization interruption:
Intconnect (inum_to_ivec (9 + 0x20), int9handler, 0);/* bind the interrupt function */
Sysintenablepic (9);/* enable interruption on the 9th */ Interrupt function prototype:
Void int9handler (int param);/* do not call the blocking function in the interrupt function */ |
