GI.GLib.Structs.MappedFile

The MappedFile represents a file mapping created with mappedFileNew. It has only private members and should not be accessed directly.

Exported types

newtype MappedFile

Memory-managed wrapper type.

Constructors

MappedFile (ManagedPtr MappedFile)

Instances

BoxedObject MappedFile

Defined in GI.GLib.Structs.MappedFile

Methods

boxedType :: MappedFile -> IO GType

noMappedFile :: Maybe MappedFile

A convenience alias for Nothing :: Maybe MappedFile.

Methods

free

mappedFileFree

Arguments

:: (HasCallStack, MonadIO m)

=> MappedFile

file: a MappedFile

-> m ()

Deprecated: (Since version 2.22)Use mappedFileUnref instead.

This call existed before MappedFile had refcounting and is currently exactly the same as mappedFileUnref.

Since: 2.8

getBytes

mappedFileGetBytes

Arguments

:: (HasCallStack, MonadIO m)

=> MappedFile

file: a MappedFile

-> m Bytes

Returns: A newly allocated Bytes referencing data from file

Creates a new Bytes which references the data mapped from file. The mapped contents of the file must not be modified after creating this bytes object, because a Bytes should be immutable.

Since: 2.34

getContents

mappedFileGetContents

Arguments

:: (HasCallStack, MonadIO m)

=> MappedFile

file: a MappedFile

-> m Text

Returns: the contents of file, or Nothing.

Returns the contents of a MappedFile.

Note that the contents may not be zero-terminated, even if the MappedFile is backed by a text file.

If the file is empty then Nothing is returned.

Since: 2.8

getLength

mappedFileGetLength

Arguments

:: (HasCallStack, MonadIO m)

=> MappedFile

file: a MappedFile

-> m Word64

Returns: the length of the contents of file.

Returns the length of the contents of a MappedFile.

Since: 2.8

new

mappedFileNew

Arguments

:: (HasCallStack, MonadIO m)

=> [Char]

filename: The path of the file to load, in the GLib filename encoding

-> Bool

writable: whether the mapping should be writable

-> m MappedFile

Returns: a newly allocated MappedFile which must be unref'd with mappedFileUnref, or Nothing if the mapping failed. (Can throw GError)

Maps a file into memory. On UNIX, this is using the mmap() function.

If writable is True, the mapped buffer may be modified, otherwise it is an error to modify the mapped buffer. Modifications to the buffer are not visible to other processes mapping the same file, and are not written back to the file.

Note that modifications of the underlying file might affect the contents of the MappedFile. Therefore, mapping should only be used if the file will not be modified, or if all modifications of the file are done atomically (e.g. using fileSetContents).

If filename is the name of an empty, regular file, the function will successfully return an empty MappedFile. In other cases of size 0 (e.g. device files such as /dev/null), error will be set to the FileError value G_FILE_ERROR_INVAL.

Since: 2.8

newFromFd

mappedFileNewFromFd

Arguments

:: (HasCallStack, MonadIO m)

=> Int32

fd: The file descriptor of the file to load

-> Bool

writable: whether the mapping should be writable

-> m MappedFile

Returns: a newly allocated MappedFile which must be unref'd with mappedFileUnref, or Nothing if the mapping failed. (Can throw GError)

Maps a file into memory. On UNIX, this is using the mmap() function.

If writable is True, the mapped buffer may be modified, otherwise it is an error to modify the mapped buffer. Modifications to the buffer are not visible to other processes mapping the same file, and are not written back to the file.

Note that modifications of the underlying file might affect the contents of the MappedFile. Therefore, mapping should only be used if the file will not be modified, or if all modifications of the file are done atomically (e.g. using fileSetContents).

Since: 2.32

ref

mappedFileRef

Arguments

:: (HasCallStack, MonadIO m)

=> MappedFile

file: a MappedFile

-> m MappedFile

Returns: the passed in MappedFile.

Increments the reference count of file by one. It is safe to call this function from any thread.

Since: 2.22

unref

mappedFileUnref

Arguments

:: (HasCallStack, MonadIO m)

=> MappedFile

file: a MappedFile

-> m ()

Decrements the reference count of file by one. If the reference count drops to 0, unmaps the buffer of file and frees it.

It is safe to call this function from any thread.

Since 2.22