fread(3S)                                               fread(3S)



NAME
     fread, fwrite - binary input/output

SYNOPSIS
     #include <stdio.h>

     int fread (ptr, size, nitems, stream)
     char *ptr;
     int size, nitems;
     FILE *stream;

     int fwrite (ptr, size, nitems, stream)
     char *ptr;
     int size, nitems;
     FILE *stream;

DESCRIPTION
     fread copies, into an array pointed to by ptr, nitems items
     of data from the named input stream, where an item of data
     is a sequence of bytes (not necessarily terminated by a null
     byte) of length size.  fread stops appending bytes if an
     end-of-file or error condition is encountered while reading
     stream, or if nitems items have been read.  fread leaves the
     file pointer in stream, if defined, pointing to the byte
     following the last byte read if there is one.  fread does
     not change the contents of stream.

     Fwrite appends at most nitems items of data from the array
     pointed to by ptr to the named output stream.  Fwrite stops
     appending when it has appended nitems items of data or if an
     error condition is encountered on stream.  Fwrite does not
     change the contents of the array pointed to by ptr.

     The argument size is typically sizeof(*ptr) where the
     pseudo-function sizeof specifies the length of an item
     pointed to by ptr.  If ptr points to a data type other than
     char it should be cast into a pointer to char.

SEE ALSO
     read(2), write(2), fopen(3S), getc(3S), gets(3S),
     printf(3S), putc(3S), puts(3S), scanf(3S).

DIAGNOSTICS
     fread and fwrite return the number of items read or written.
     If size or nitems is non-positive, no characters are read or
     written and 0 is returned by both fread and fwrite.









Page 1                        CX/UX Programmer's Reference Manual