Add get-bytevector-some!.

* libguile/r6rs-ports.c (scm_get_bytevector_some_x): New procedure.
* libguile/r6rs-ports.h (scm_get_bytevector_some_x): Add prototype.
(scm_unget_bytevector): Move prototype next to 'scm_get_bytevector_some_x'.
* module/ice-9/binary-ports.scm: Export 'get-bytevector-some!'.
* doc/ref/api-io.texi (Binary I/O): Document it.

1 files changed, 9 insertions, 1 deletions

diff --git a/doc/ref/api-io.texi b/doc/ref/api-io.texi
index 24890a12e..270a97075 100644
--- a/doc/ref/api-io.texi
+++ b/doc/ref/api-io.texi
@@ -1,7 +1,7 @@
 @c -*-texinfo-*-
 @c This is part of the GNU Guile Reference Manual.
 @c Copyright (C)  1996, 1997, 2000, 2001, 2002, 2003, 2004, 2007, 2009,
-@c   2010, 2011, 2013, 2016  Free Software Foundation, Inc.
+@c   2010, 2011, 2013, 2016, 2019  Free Software Foundation, Inc.
 @c See the file guile.texi for copying conditions.
 
 @node Input and Output
@@ -194,6 +194,14 @@ new bytevector containing some of the available bytes (at least one),
 and update the port position to point just past these bytes.
 @end deffn
 
+@deffn {Scheme Procedure} get-bytevector-some! port bv start count
+@deffnx {C Function} scm_get_bytevector_some_x (port, bv, start, count)
+Read up to @var{count} bytes from @var{port}, blocking as necessary
+until at least one byte is available or an end-of-file is reached.
+Store them in @var{bv} starting at index @var{start}.  Return the number
+of bytes actually read, or an end-of-file object.
+@end deffn
+
 @deffn {Scheme Procedure} get-bytevector-all port
 @deffnx {C Function} scm_get_bytevector_all (port)
 Read from @var{port}, blocking as necessary, until the end-of-file is