fread
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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 elements 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 elements of data, each size bytes long, to the stream pointed to by stream, obtaining them from the location given by ptr.

For non-locking counterparts, see unlocked_stdio(3).

RETURN VALUE

fread() and fwrite() return the number of items successfully read or written (i.e., not the number of characters). If an error occurs, or the end-of-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.

CONFORMING TO

C89, POSIX.1-2001.

SEE ALSO

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

COLOPHON

This page is part of release 2.79 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/.

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