abcd0x00

The  following  symbolic names for the values of type mode_t shall also
be defined.

File type:

S_IFMT Type of file.

S_IFBLK
       Block special.

S_IFCHR
       Character special.

S_IFIFO
       FIFO special.

S_IFREG
       Regular.

S_IFDIR
       Directory.
...

The following macros shall be provided to test whether a file is of the
specified  type.  The  value  m  supplied to the macros is the value of
st_mode from a stat structure.  The macro shall evaluate to a  non-zero
value if the test is true; 0 if the test is false.

S_ISBLK(m)
       Test for a block special file.

S_ISCHR(m)
       Test for a character special file.

S_ISDIR(m)
       Test for a directory.

S_ISFIFO(m)
       Test for a pipe or FIFO special file.

S_ISREG(m)
       Test for a regular file.

S_ISLNK(m)
       Test for a symbolic link.

S_ISSOCK(m)
       Test for a socket.

существует ли что-то вроде этого для Си?

#include <stdio.h>

int main(void)
{
    char s[4] = "1234";

    printf("%d\n", (s[0] - '0') + (s[1] - '0'));
    printf("%d\n", (s[2] - '0') + (s[3] - '0'));
    return 0;
}

[guest@localhost c]$ .ansi t.c -o t
[guest@localhost c]$ ./t
3
7
[guest@localhost c]$

int n = *w++;