Using the standard C API

This description is necessarily almost as brief and incomplete as our discussion of POSIX earlier. For a complete description of the facilities in <stdio.h>, you'll have to consult another source, such as cppreference.com or your local man pages.

In the "C-style" API, POSIX file descriptors are given a new name: the thing corresponding to a file descriptor is called FILE, and the thing corresponding to an integer file descriptor handle is (naturally) called FILE*. Just as in the POSIX API, though, you'll never construct an instance of FILE yourself.

To create a new FILE object and get a pointer to it, you use the fopen function; for example, FILE *fp = fopen("myfile.txt", "r"). The second argument is a string (that is, a pointer to a null-terminated array of characters--generally, you'll just use a string literal, as I did here), which must be one of the following:

• "r": This is equivalent to POSIX O_RDONLY. Open for reading. Fail (that is, return nullptr) if the...