1 files changed, 51 insertions, 0 deletions
diff --git a/docs/nspr/reference/pr_available64.rst b/docs/nspr/reference/pr_available64.rst
new file mode 100644
index 0000000000..7ee2dd07a7
--- /dev/null
+++ b/docs/nspr/reference/pr_available64.rst
@@ -0,0 +1,51 @@
+PR_Available64
+==============
+
+Determines the number of bytes (expressed as a 32-bit integer) that are
+available for reading beyond the current read-write pointer in a
+specified file or socket.
+
+
+Syntax
+------
+
+.. code::
+
+   #include <prio.h>
+
+   PRInt64 PR_Available64(PRFileDesc *fd);
+
+
+Parameter
+~~~~~~~~~
+
+The function has the following parameter:
+
+``fd``
+   Pointer to a :ref:`PRFileDesc` object representing a file or socket.
+
+
+Returns
+~~~~~~~
+
+The function returns one of the following values:
+
+-  If the function completes successfully, it returns the number of
+   bytes that are available for reading. For a normal file, these are
+   the bytes beyond the current file pointer.
+-  If the function fails, it returns the value -1. The error code can
+   then be retrieved via :ref:`PR_GetError`.
+
+
+Description
+-----------
+
+:ref:`PR_Available64` works on normal files and sockets. :ref:`PR_Available`
+does not work with pipes on Win32 platforms.
+
+
+See Also
+--------
+
+If the number of bytes available for reading is within the range of a
+32-bit integer, use :ref:`PR_Available`.