[C++] Sync API changes (#633)

Added:

  * NotCurses: can_utf8 (`notcurses_canutf8`)
  * NotCurses: debug (`notcurses_debug`)
  * Plane: center_abs (`ncplane_center_abs`)
  * Plane: set_channels (`ncplane_set_channels`)
  * Plane: set_attr (`ncplane_set_attr`)
  * Reader: clear (`ncreader_clear`)

Changed:

  * USAGE.md: clarfied when C++ throws exceptions

USAGE.md

@@ -2557,6 +2557,6 @@ struct ncvisual* ncvisual_from_plane(struct ncplane* n);
 Marek Habersack has contributed (and maintains) C++ wrappers installed to
 `include/ncpp/`, `libnotcurses++.so`, and `libnotcurses++.a`.
 
-In their default mode, these wrappers never throw exceptions. If
-`NCPP_EXCEPTIONS_PLEASE` is defined prior to including any NCPP headers,
-they will throw exceptions.
+In their default mode, these wrappers throw exceptions only from the type 
+constructors (RAII). If `NCPP_EXCEPTIONS_PLEASE` is defined prior to including 
+any NCPP headers, they will throw exceptions.

include/ncpp/NotCurses.hh

@@ -83,6 +83,11 @@ namespace ncpp
 
 		bool stop ();
 
+		bool can_utf8 () const noexcept
+		{
+			return notcurses_canutf8 (nc);
+		}
+
 		bool can_fade () const noexcept
 		{
 			return notcurses_canfade (nc);
@@ -205,6 +210,11 @@ namespace ncpp
 			notcurses_drop_planes (nc);
 		}
 
+		void debug (FILE *debugfp) const noexcept
+		{
+			notcurses_debug (nc, debugfp);
+		}
+
 		Plane* get_stdplane () noexcept
 		{
 			return new Plane (notcurses_stdplane (nc), true);

include/ncpp/Plane.hh

@@ -115,6 +115,11 @@ namespace ncpp
 			return plane;
 		}
 
+		void center_abs (int *y, int *x) const noexcept
+		{
+			ncplane_center_abs (plane, y, x);
+    }
+
 		ncplane* to_ncplane () noexcept
 		{
 			return plane;
@@ -652,6 +657,16 @@ namespace ncpp
 			return ncplane_fg_alpha (plane);
 		}
 
+		void set_channels (uint64_t channels) const noexcept
+		{
+			ncplane_set_channels (plane, channels);
+		}
+
+		void set_attr (uint32_t attrword) const noexcept
+		{
+			ncplane_set_attr (plane, attrword);
+		}
+
 		bool set_fg_alpha (int alpha) const NOEXCEPT_MAYBE
 		{
 			return error_guard (ncplane_set_fg_alpha (plane, alpha), -1);
@@ -1085,4 +1100,4 @@ namespace ncpp
 		friend class Tablet;
 	};
 }
-#endif
+#endif

include/ncpp/Reader.hh

@@ -44,6 +44,12 @@ namespace ncpp
 				ncreader_destroy (reader, nullptr);
 		}
 
+		bool clear () const NOEXCEPT_MAYBE
+		{
+			bool ret = ncreader_clear (reader) != 0;
+			return error_guard_cond<bool, bool> (ret, ret);
+		}
+
 		char* get_contents () const noexcept
 		{
 			return ncreader_contents(reader);