将2个字节的十六进制发送到远程串行

Question

I only need to send a hexadecimal like this to a remote serial for the device to accept it.

2 byte hexadecimal I need to send is:

181E

I can telnet to the remote serial and send that command:

telnet x.x.x.x port

181E

I get a response back which is okay.

How can I do this in linux c?

I want to use the write function.

err = write(socket,181E,2);

Or How can I store the 2 byte decimal to a variable so It will be read as 181E?

int this_is_2_bytes = 181E; // Is this correct?

err = write(socket, this_is_2_bytes, sizeof(this_is_2_bytes));

Answer 1

You need to send a hexadecimal string . So,

const char cmd[] = "181E";
err = write(socket, cmd, strlen(cmd)); 

Answer 2

No, writing an int is not correct on all systems. Write a two-element byte array.

Answer 3

write（）函数需要一个指针作为第二个参数，并将其存储在字符数组中。