NAME
fread, fwrite - binary stream input/output SYNOPSIS
#include
sizet fread(void *ptr, sizet size, sizet nmemb, FILE *stream); sizet fwrite(const void *ptr, sizet size, sizet nmemb, FILE *stream); DESCRIPTION The function fread() reads nmemb elements of data, each size bytes long, from the stream pointed to by stream, storing them at the loca‐ tion given by ptr. The function fwrite() writes nmemb elements 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 unlockedstdio(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
C89, POSIX.1-2001. SEE ALSO read(2), write(2), feof(3), ferror(3), unlockedstdio(3) COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
GNU 2012-03-30 FREAD(3)