instance method
IO::Buffer#private?
private? → true or false
io_buffer.c
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static VALUE
rb_io_buffer_private_p(VALUE self)
{
struct rb_io_buffer *buffer = NULL;
TypedData_Get_Struct(self, struct rb_io_buffer, &rb_io_buffer_type, buffer);
return RBOOL(buffer->flags & RB_IO_BUFFER_PRIVATE);
}
If the buffer is private, meaning modifications to the buffer will not be replicated to the underlying file mapping.
Example
# Create a test file: File.write('test.txt', 'test') # Create a private mapping from the given file. Note that the file here # is opened in read-only mode, but it doesn't matter due to the private # mapping: buffer = IO::Buffer.map(File.open('test.txt'), nil, 0, IO::Buffer::PRIVATE) # => #<IO::Buffer 0x00007fce63f11000+4 MAPPED PRIVATE> # Write to the buffer (invoking CoW of the underlying file buffer): buffer.set_string('b', 0) # => 1 # The file itself is not modified: File.read('test.txt') # => "test"