Reading from serial port inside a method yields different results than from main

This is a discussion on Reading from serial port inside a method yields different results than from main within the C++ Programming forums, part of the General Programming Boards category; Hello, I am developing an application that reads data from a serial port (on Ubuntu), and below is the relevant ...

  1. #1
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    Reading from serial port inside a method yields different results than from main

    Hello,

    I am developing an application that reads data from a serial port (on Ubuntu), and below is the relevant code used.

    Code:
    int fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NDELAY);
    fcntl(fd, F_SETFL, 0);
    int value[2];
    read(fd, value, 2);
    printf("%x %x", value[0], value[1];
    When I put this inside my main, it works just fine. However, if I put the exact same code inside a method, it will output weird data. I have no idea why that's so, if anyone has any guidance it would be greatly appreciated.

    Thanks

  2. #2
    Algorithm Dissector iMalc's Avatar
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    I can tell you that without a shadow of a doubt, the problem is not from putting the code into a function. It is from doing something else wrong, like returning the address of a variable that goes out of scope.

    To spot the exact error you made, we need to see the entire function as you had it, and how you call it from main.
    My homepage
    Advice: Take only as directed - If symptoms persist, please see your debugger

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  3. #3
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    Stupid me. I was reading a different number of bytes inside the function (on the read() call), once I changed it I got the right result.

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