Question

I am working on a program in C on a linux machine that displays the file type of a file presented as an argument to the program. The program needs to determine if a file is any one of the following: directory, device, (regular) file, link, socket, or fifo. I am not exactly sure how to determine file type.

Here is my code thus far (not much):

int
main(int argc, char **argv)
{
    if( argc == 1 )     /* default: current directory */
        puts("Directory");
    else
        while( --argc > 0 )
            determine_ftype(*++argv);

    return  0;
}

Thanks!

Answer 1

Use the POSIX stat function and read the st_mode field of the structure struct stat returned by the function.

stat function:

http://pubs.opengroup.org/onlinepubs/7908799/xsh/stat.html

The structure struct stat type:

http://pubs.opengroup.org/onlinepubs/7908799/xsh/sysstat.h.html

For glibc, you can also read the section 14.9.3 Testing the Type of a File of the glibc manual:

http://www.gnu.org/software/libc/manual/html_node/Testing-File-Type.html