fread(3)                            CLIX                            fread(3)



  NAME

    fread, fwrite - Binary input/output

  LIBRARY

    Standard C Library (libc.a)

  SYNOPSIS

    #include <stdio.h>

    #include <sys/types.h>

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

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

  PARAMETERS

    ptr      Points to an array.

    size     Specifies the size of a datum in bytes.

    nitems   Specifies the number of items to be copied.

    stream   Specifies a file.

  DESCRIPTION

    The fread() function 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.  The
    fread() function stops appending bytes if an end-of-file or error
    condition is encountered while reading stream, or if nitems items have
    been read.  The fread() function leaves the file pointer in stream, if
    defined, pointing to the byte following the last byte read if there is
    one.  The fread() function does not change the contents of stream.

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



  2/94 - Intergraph Corporation                                              1

  fread(3)                            CLIX                            fread(3)



    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.

  EXAMPLES

    FILE *fp *fopen()
    char buffer [80];
    int nread;
    fp=fopen("scratch","r");
    nread=fread(buffer,sizeof(char),80,fp);


  RETURN VALUES

    The fread() and fwrite() functions return the number of items read or
    written.  If nitems is not positive, no characters are read or written and
    0 is returned by both fread() and fwrite().

  RELATED INFORMATION

    Functions:  read(2), write(2), fopen(3), getc(3), gets(3), printf(3),
    putc(3), puts(3), scanf(3), stdio(3)





























  2                                              Intergraph Corporation - 2/94