std.mmfile

Read and write memory mapped files.

Memory mapped files are a mechanism in operating systems that allows file access through virtual memory. After opening a file with MmFile, the contents can be read from or written to with standard slice / pointer operations. Changes to the memory are automatically reflected in the underlying file.

Memory mapping can increase I/O performance of large files, compared to buffered read / write operations from std.file and std.stdio. However, I/O errors are not handled as safely: when for example the disk that the file is on gets removed, reading from it may result in a segfault.

Copyright

License

Boost License 1.0.

Authors

Walter Bright,

Matthew Wilson References: https://en.wikipedia.org/wiki/Memory-mapped_file Source: std/mmfile.d

class MmFile

Types 1

classMmFile

MmFile objects control the memory mapped file resource.

Methods

void flush()

ulong length() @property constGives size in bytes of the memory mapped file.

Mode mode()Read-only property returning the file mode.

void[] opSlice()Returns entire file contents as an array.

void[] opSlice(ulong i1, ulong i2)Returns slice of file contents as an array.

ubyte opIndex(ulong i)Returns byte at index i in file.

ubyte opIndexAssign(ubyte value, ulong i)Sets and returns byte at index i in file to value.

Constructors

this(string filename)Open memory mapped file filename for reading. File is closed when the object instance is deleted. Throws: - On POSIX, ErrnoException. - On Windows, WindowsException.

this(string filename,  Mode mode,  ulong  size,  void *  address,
             size_t window =  0)

Open memory mapped file filename in mode. File is closed when the object instance is deleted. Params: filename = name of the file. If null, an anonymous file mapping is created. mode = access mode ...

Destructors

~thisFlushes pending output and closes the memory mapped file.

Nested Templates

ModeThe mode the memory mapped file is opened with.