bpo-41625: Expose the splice() system call in the os module (GH-21947)
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index 6c7ae0c..75a8ed4 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -1419,6 +1419,38 @@
.. versionadded:: 3.3
+.. function:: splice(src, dst, count, offset_src=None, offset_dst=None)
+
+ Transfer *count* bytes from file descriptor *src*, starting from offset
+ *offset_src*, to file descriptor *dst*, starting from offset *offset_dst*.
+ At least one of the file descriptors must refer to a pipe. If *offset_src*
+ is None, then *src* is read from the current position; respectively for
+ *offset_dst*. The offset associated to the file descriptor that refers to a
+ pipe must be ``None``. The files pointed by *src* and *dst* must reside in
+ the same filesystem, otherwise an :exc:`OSError` is raised with
+ :attr:`~OSError.errno` set to :data:`errno.EXDEV`.
+
+ This copy is done without the additional cost of transferring data
+ from the kernel to user space and then back into the kernel. Additionally,
+ some filesystems could implement extra optimizations. The copy is done as if
+ both files are opened as binary.
+
+ Upon successful completion, returns the number of bytes spliced to or from
+ the pipe. A return value of 0 means end of input. If *src* refers to a
+ pipe, then this means that there was no data to transfer, and it would not
+ make sense to block because there are no writers connected to the write end
+ of the pipe.
+
+ .. availability:: Linux kernel >= 2.6.17 or glibc >= 2.5
+
+ .. versionadded:: 3.10
+
+
+.. data:: SPLICE_F_MOVE
+ SPLICE_F_NONBLOCK
+ SPLICE_F_MORE
+
+
.. function:: readv(fd, buffers)
Read from a file descriptor *fd* into a number of mutable :term:`bytes-like