passing arg 1 of `write' makes integer from pointer withouta cast

lung_sen · #1 28-Mar-2005, 20:26

Hi, I encounter this problem, where there are 10 warnings for every read/write operation I've done. I'm using GCC compiler to compile it. Here is my code. As far as I know, it means that the first argument (char*)&ConfValue need to be integer, but It was works in another code, declared as char. I really dont know how to debug it.
Anyone can help me? Thank you

lung_sen · #2 28-Mar-2005, 20:31

Hi this is the code, spicode.doc. Pls take a look. Thank u

nkhambal · #3 28-Mar-2005, 21:10

Hi,

You have confused between "fopen" and "open".
open returns file descriptor for the opened file which is an integer. You are casting it to be a pointer. It is wrong. "fopen" returns pointer not "open"

CPP / C++ / C Code:

 FILE *fd;

    if( (fd =(FILE *) open("/dev/spi",O_RDWR)) < 0)
    {
        printf("Error opening fd=%d\n",fd);
        exit(1);
    }

should be

CPP / C++ / C Code:


int fd;

    if( (fd = open("/dev/spi",O_RDWR)) < 0)
    {
        printf("Error opening fd=%d\n",fd);
        exit(1);
    }

So is the problem with read() and write(). They expect first argument to be an integer file descriptor "fd" where as you are passing a pointer "fd". Hence the warnings.

Correcting above "open" code should supress all the warnings.

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