The explain_fstatvfs_or_die function is used to call the
fstatvfs(2) system call. On failure an explanation will be printed
to stderr, obtained from the explain_fstatvfs(3) function,
and then the process terminates by calling exit(EXIT_FAILURE).
The explain_fstatvfs_on_error function is used to call the
fstatvfs(2) system call. On failure an explanation will be printed
to stderr, obtained from the explain_fstatvfs(3) function,
but still returns to the caller.
fildes
The fildes, exactly as to be passed to the fstatvfs(2) system call.
data
The data, exactly as to be passed to the fstatvfs(2) system call.
RETURN VALUE
The explain_fstatvfs_or_die function only returns on success, see
fstatvfs(2) for more information. On failure, prints an explanation
and exits, it does not return.
The explain_fstatvfs_on_error function always returns the value
return by the wrapped fstatvfs(2) system call.
EXAMPLE
The explain_fstatvfs_or_die function is intended to be used in a
fashion similar to the following example: