Re: Re: Re: Re: write and read functions in asyn

[Érico Nogueira Rolim via Tech-talk <tech-talk at aps.anl.gov>]

Hi Gao,

Your latest message got sent to spam for me, and might have been for others as well, which would explain why you didn't get any answers.

You can find the implementation of ports for IP (both TCP and UDP) and serial interfaces, with their respective low level functions, in https://github.com/epics-modules/asyn/tree/master/asyn/drvAsynSerial

I expect the functions you'll find the most interesting in those files to be writeIt and readIt.

Cheers,

Érico

On 13/04/2025 01:17, 高振华 via Tech-talk wrote:

Hi Mark,

Thank you for your help.

My question is: Where are the lowest level functions used by asyn for reading and writing RS232、TCP and other communication interfaces?

such as writeFile、readFile or fprintf,and so on,Where were these functions called.

Best regards

Gao

-----原始邮件-----
发件人: "Mark Rivers" <rivers at cars.uchicago.edu>
发送时间: 2025-04-13 00:46:26 (星期日)
收件人: 高振华 <gaozh at ihep.ac.cn>
抄送: "tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov>
主题: Re: Re: write and read functions in asyn

• Does the (* write) function in asynInt32.h inherit from the writeIt function in drvAsynSerialPort.c (when accessing a serial port)?

No, the drvAsynSerialPort driver does not implement the asynInt32 interface.

It implements the asynCommon inteface here.  All drivers must implement asynCommon:

https://github.com/epics-modules/asyn/blob/413a3b834b3b3cfd01b1098a023fb01fd9396a59/asyn/drvAsynSerial/drvAsynSerialPort.c#L1096

It implements the asynOption interface here:

https://github.com/epics-modules/asyn/blob/413a3b834b3b3cfd01b1098a023fb01fd9396a59/asyn/drvAsynSerial/drvAsynSerialPort.c#L1099

It implements the asynOctet interface here:

https://github.com/epics-modules/asyn/blob/413a3b834b3b3cfd01b1098a023fb01fd9396a59/asyn/drvAsynSerial/drvAsynSerialPort.c#L1123

Those are the only interfaces that it implements.

This is a simple example driver that implements the asynInt32 interface:

https://github.com/epics-modules/asyn/blob/master/testEpicsApp/src/int32Driver.c

Many drivers now use the asynPortDriver base class.  It greatly simplifies the code required to register and implement asyn interfaces.  This is the code:

https://github.com/epics-modules/asyn/tree/master/asyn/asynPortDriver

This is the documentation:

https://epics-modules.github.io/asyn/asynPortDriver.html

This is a real driver for a simple device that implements the asynInt32 interface using asynPortDriver.

https://github.com/epics-modules/dac128V/blob/master/dac128VApp/src/drvDac128V.cpp

Mark

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From: 高振华 <gaozh at ihep.ac.cn>
Sent: Saturday, April 12, 2025 6:39 AM
To: Mark Rivers <rivers at cars.uchicago.edu>
Cc: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: Re: Re: write and read functions in asyn

 

Hi Mark,

Thanks,

Does the (* write) function in asynInt32.h inherit from the writeIt function in drvAsynSerialPort.c (when accessing a serial port)?

static asynStatus writeIt(void *drvPvt, asynUser *pasynUser, const char *data, size_t numchars,size_t *nbytesTransfered)

{
    ttyController_t *tty = (ttyController_t *)drvPvt;

    int thisWrite;

    int nleft = numchars;

    int timerStarted = 0;

    asynStatus status = asynSuccess;

    assert(tty);

    ...

Gao Zhenhua

-----原始邮件-----
发件人: "Mark Rivers" <rivers at cars.uchicago.edu>
发送时间: 2025-04-11 11:23:41 (星期五)
收件人: "tech-talk at aps.anl.gov" <tech-talk at aps.anl.gov>, 高振华 <gaozh at ihep.ac.cn>
主题: Re: write and read functions in asyn

Those functions are implemented by the asyn driver.  asynInt32.h defines the interface, but the implementation is done in each driver.

They are analogous to C++ pure virtual functions that each derived class must implement.

Mark

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of 高振华 via Tech-talk <tech-talk at aps.anl.gov>
Sent: Thursday, April 10, 2025 8:46 PM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: write and read functions in asyn

 

Hi all,

I saw the prototype declarations for the write and read functions in this. h file(asyn/asyn/interfaces/asynInt32.h),

But I couldn't find the bodies of the write and read functions,

Does anyone know where it is?

typedef struct asynInt32 {

    asynStatus (*write)(void *drvPvt, asynUser *pasynUser, epicsInt32 value);

    asynStatus (*read)(void *drvPvt, asynUser *pasynUser, epicsInt32 *value);

    asynStatus (*getBounds)(void *drvPvt, asynUser *pasynUser,

                           epicsInt32 *low, epicsInt32 *high);

    asynStatus (*registerInterruptUser)(void *drvPvt,asynUser *pasynUser,

                           interruptCallbackInt32 callback, void *userPvt,

                           void **registrarPvt);

    asynStatus (*cancelInterruptUser)(void *drvPvt, asynUser *pasynUser,

                           void *registrarPvt);

} asynInt32;

Thanks,

Gao Zhenhua

--

BSRF

Email:gaozh at ihep.ac.cn

---

      

祝好！

高振华

电话：010-88235426

Email:gaozh at ihep.ac.cn

---

      

祝好！

高振华

电话：010-88235426

Email:gaozh at ihep.ac.cn

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