How to read from stdout of another process in linux api?

Question

linux

There is the following code on WinApi:

std::string getResponseFromEngine(position)
{
    WriteFile(pipin_w, position.c_str(), position.length(),&writ, NULL);
    Sleep(500);
    PeekNamedPipe(pipout_r, buffer,sizeof(buffer), &read, &available, NULL);   
    do
    {   
        ZeroMemory(buffer, sizeof(buffer));
        if(!ReadFile(pipout_r, buffer, sizeof(buffer), &read, NULL) || !read) break; 
        buffer[read] = 0;    
        str+=(char*)buffer;
    }
    while(read >= sizeof(buffer));
    return str;
}

How can it be replaced by analogues in linux api?
The situation is as follows: there is a running application and it is necessary to send information to its stdin and read from stdout.

Answer 1

Capture the output of a child process in C
I think the same can be done for stdin.

Answer 2

In Linux, there are named and unnamed pipes in the same way, the API, of course, is different, but the essence does not change.