FileOutputStream.fromFile constructor

Creates a file output stream to write to the specified File object.

Parameters

• file: The file to be opened for writing
• append: If true, bytes will be written to the end of the file rather than the beginning (default: false)

Example

final file = File('output.bin');
final output = FileOutputStream.fromFile(file);

// Append mode
final appendOutput = FileOutputStream.fromFile(file, append: true);

Throws IOException if the file exists but is a directory rather than a regular file, does not exist but cannot be created, or cannot be opened for any other reason.

A file output stream is an output stream for writing data to a File or to a file descriptor.

FileOutputStream is meant for writing streams of raw bytes such as image data. For writing streams of characters, consider using FileWriter.

Example Usage

// Writing binary data
final output = FileOutputStream('output.bin');
try {
  final data = Uint8List.fromList([0x89, 0x50, 0x4E, 0x47]); // PNG header
  await output.writeBytes(data);
  await output.flush();
} finally {
  await output.close();
}

// Appending to existing file
final output = FileOutputStream('log.txt', append: true);
try {
  await output.writeString('New log entry\n');
  await output.flush();
} finally {
  await output.close();
}