FREAD(3)                                                     Linux Programmer's Manual                                                    FREAD(3)

NAME

       fread, fwrite - binary stream input/output

SYNOPSIS

       #include <stdio.h>

       size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);

       size_t fwrite(const void *ptr, size_t size, size_t nmemb,
                     FILE *stream);

DESCRIPTION

       The  function  fread()  reads nmemb items of data, each size bytes long, from the stream pointed to by stream, storing them at the location
       given by ptr.

       The function fwrite() writes nmemb items of data, each size bytes long, to the stream pointed to by stream, obtaining them from  the  loca-
       tion given by ptr.

       For nonlocking counterparts, see unlocked_stdio(3).

RETURN VALUE

       On  success, fread() and fwrite() return the number of items read or written.  This number equals the number of bytes transferred only when
       size is 1.  If an error occurs, or the end of the file is reached, the return value is a short item count (or zero).

       fread() does not distinguish between end-of-file and error, and callers must use feof(3) and ferror(3) to determine which occurred.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       +------------------+---------------+---------+
       |Interface         | Attribute     | Value   |
       +------------------+---------------+---------+
       |fread(), fwrite() | Thread safety | MT-Safe |
       +------------------+---------------+---------+
CONFORMING TO

       POSIX.1-2001, POSIX.1-2008, C89.

SEE ALSO

       read(2), write(2), feof(3), ferror(3), unlocked_stdio(3)

COLOPHON

       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

GNU                                                                 2015-07-23                                                            FREAD(3)