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