用C进行串口读写 [英] Serial port reading and writing with C

问题描述

我正在编写一个C程序，该程序将在串行端口中进行读写操作.每次写操作之后都会有一个读操作，该读操作将包含基于写操作的数据.我将执行大约16种不同的写操作，每个写操作之后都会进行读操作.

I am writing a C program that will read and write from/to a serial port. Each write will be followed by a read which will contain data based on the write. I will have about 16 different writes to perform, each followed by a read.

我对串行编程还是陌生的，并且正在尝试确定如何实现此目的.程序是否应该在每次写/读期间阻塞(基本上是一个大的while(1)读和写循环)?

I am still new to serial programming and am trying to determine how to approach this. Should the program block during each write/read (basically having a big while(1) loop of writes and reads)?

是否有可能一个线程发送写操作而另一个线程执行读操作?可以创建一个回调来允许线程知道何时可以从串行端口读取数据吗?

Is it possible to have one thread sending writes while another thread performs the reads? Can a callback be created for allowing a thread to know when data is available to be read from the serial port?

感谢您的帮助.

操作系统:Linux

OS: Linux

推荐答案

这听起来像一个简单的循环，只需进行读取和写入即可.如果您想要更多控制权(例如，在X秒钟无输入后编写保持活动状态)，请使用 select 或 poll ；它们允许您在有数据可用的情况下感知"，因此 read 不会阻塞(但是，如果select和read之间发生某些情况，则您仍应非阻塞地读取).在这种情况下，多线程没有意义.

It sounds like a simple loop with a read and a write will be enough. If you want more control (like writing a keep-alive after X seconds of no input) use select or poll; they allow you to "sense" if data is available, so a read will not block (however, you should still read non-blocking in case something happens between the select and the read). Multithreading doesn't make sense in this case.

select 和 poll 还可让您测试写入是否会阻塞；再次，请确保写非阻塞.通常，除了 select 或 poll 之外，您通常都不希望进程挂在某些阻塞的系统调用中.(至少我没有)

select and poll also allow you to test if writing will block; again, write non-blocking just to be sure. You generally don't want your process to be hanging in some blocking system call, ever, apart from select or poll, that is. (at least, I don't)

使用 ioctl 在串行线路上设置各种参数.使用

Use ioctl to set various parameters on the serial line. Use

$ strace -o /tmp/strace.minicom -f minicom

启动minicom(或任何其他终端程序)，并查看它们如何使工作正常(如果您遇到问题).和往常一样，请参阅 man select/poll/read/ioctl 了解更多信息.

to launch minicom (or any other terminal program) and see what they do to get things working, if you're stuck. And as always, see man select/poll/read/ioctl for more information.

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