fwrite

Writes elements to a stream.

Library:LibC
Classification:ANSI
Service:File and Directory I/O

Syntax

  #include <stdio.h> 
   
  size_t fwrite (
     const void   *buf,
     size_t        elsize,
     size_t        nelem,
     FILE         *fp);

Parameters

buf

(IN) Points to the buffer containing the data to write.

elsize

(IN) Specifies the size (in bytes) of each element.

nelem

(IN) Specifies the number of elements.

fp

(IN) Points to the file.

Return Values

If successful, returns the number of complete elements that are successfully written. If a write error occurs, the number returned can be less than the requested number. If a write error occurs, fwrite sets the error indicator for the stream and sets errno to one of the following:

Decimal

Constant

Description

4

EBADF

The file descriptor is not a valid file descriptor open for writing.

5

ENOMEM

Insufficient storage space is available.

12

ENOSPC

No free space remains on the device containing the file.

24

EAGAIN

The O_NONBLOCK flag is set for the file descriptor, and the process cannot immediately perform the write operation.

25

ENXIO

A request was made of a nonexistent device, or the request was outside the capabilities of the device.

28

EIO

A physical I/O error has occurred.

32

EPIPE

An attempt was made to write to a pipe or FIFO that is not open for reading by any process.

63

EINTR

A signal interrupted the write operation.

71

EFBIG

An attempt was made to write to a file that exceeds the maximum file size.

See Also