fread(3S)              UNIX System V(C Development Set)               fread(3S)


NAME
      fread, fwrite - binary input/output

SYNOPSIS
      #include <stdio.h>

      sizet fread (void *ptr, sizet size, sizet nitems, FILE *stream);

      sizet fwrite (const void *ptr, sizet size, sizet nitems, FILE
          *stream);

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

      fwrite writes to the named output stream at most nitems items of data
      from the array pointed to by ptr, where an item of data is a sequence of
      bytes (not necessarily terminated by a null byte) of length size.  fwrite
      stops writing when it has written 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.  fwrite increments the data-pointer in
      stream by the number of bytes written.  fwrite returns the number of
      items written.

      If size or nitems is zero, then fread and fwrite return a value of 0 and
      do not effect the state of stream.

      The ferror or feof routines must be used to distinguish between an error
      condition and end-of-file condition.

SEE ALSO
      exit(2), lseek(2), read(2), write(2), abort(3C), fclose(3S), fopen(3S),
      getc(3S), gets(3S), printf(3S), putc(3S), puts(3S), scanf(3S), stdio(3S).

DIAGNOSTICS
      If an error occurs, the error indicator for stream is set.












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