How to read linux file permission programmatically in C/C++

Question

How can I read linux file permission programmatically instead using \"ls\" then parse the result.

Answer 1

This is a function in C, that returns file permissions in the string format "rwxr-r--"

char* permissions(char *file){
    struct stat st;
    char *modeval = malloc(sizeof(char) * 9 + 1);
    if(stat(file, &st) == 0){
        mode_t perm = st.st_mode;
        modeval[0] = (perm & S_IRUSR) ? 'r' : '-';
        modeval[1] = (perm & S_IWUSR) ? 'w' : '-';
        modeval[2] = (perm & S_IXUSR) ? 'x' : '-';
        modeval[3] = (perm & S_IRGRP) ? 'r' : '-';
        modeval[4] = (perm & S_IWGRP) ? 'w' : '-';
        modeval[5] = (perm & S_IXGRP) ? 'x' : '-';
        modeval[6] = (perm & S_IROTH) ? 'r' : '-';
        modeval[7] = (perm & S_IWOTH) ? 'w' : '-';
        modeval[8] = (perm & S_IXOTH) ? 'x' : '-';
        modeval[9] = '\0';
        return modeval;     
    }
    else{
        return strerror(errno);
    }   
}