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How can I write to a file with no buffer?
In a simple example, the application would open a file for write access with the FILE_FLAG_NO_BUFFERING flag and then perform a call to the WriteFile function using a data buffer defined within the application. This local buffer is, in these circumstances, effectively the only file buffer that exists for this operation.
How do I save a file to a buffer?
To save a file, the original file is replaced by writing the buffer to disk. The :new command creates a new window displaying the contents of a new (empty) buffer. To list all buffers use the :ls command. Each buffer is assigned a number that is displayed in the first column. The second column describes the state of the buffer.
What happens to the buffer when a file is edited?
When a file is edited, the file is read into a new buffer that holds a temporary copy of the file (or an empty buffer for a new file). Editing makes changes to the buffer.
Do you need to turn off file buffering?
For devices that do not seek, such as named pipes or communications devices, turning off buffering may not require any particular alignment. Any limitations or efficiencies that may be gained by alignment in that case are dependent on the underlying technology.
What does it mean to have a buffer in a file?
This topic covers the various considerations for application control of file buffering, also known as unbuffered file input/output (I/O). File buffering is usually handled by the system behind the scenes and is considered part of file caching within the Windows operating system unless otherwise specified.
How are read and write buffers allocated in Win32?
Because buffer addresses for read and write operations must be sector-aligned, the application must have direct control of how these buffers are allocated. One way to sector-align buffers is to use the VirtualAlloc function to allocate the buffers. Consider the following:
How big can a file buffer be in Win32?
For example, if the sector size is 512 bytes, an application can request reads and writes of 512, 1,024, 1,536, or 2,048 bytes, but not of 335, 981, or 7,171 bytes.