Add const to places.

Note that I did NOT add const to non-pointer/non-reference arguments
in function declarations (without a following definition), as they do
not mean anything there.

8 files changed, 87 insertions, 102 deletions

diff --git a/c/common.cpp b/c/common.cpp
index 02feecf..7a1438d 100644
--- a/c/common.cpp
+++ b/c/common.cpp
@@ -2,7 +2,7 @@
 
 #include "common.h"
 
-Win32Error::Win32Error(DWORD dwErr)
+Win32Error::Win32Error(const DWORD dwErr)
 {
 	m_dwErr = dwErr;
 	FormatMessageA(
diff --git a/c/common.h b/c/common.h
index 76f3d6e..d6e5848 100644
--- a/c/common.h
+++ b/c/common.h
@@ -30,7 +30,7 @@ private:
 	HMODULE m_hModule;
 };
 
-inline int Cmp(int a, int b)
+inline int Cmp(const int a, const int b)
 {
 	if (a == b) return 0;
 	if (a > b) return 1;
@@ -38,7 +38,7 @@ inline int Cmp(int a, int b)
 }
 
 /* Return integer scaled for current DPI. */
-inline int Dpi(int i)
+inline int Dpi(const int i)
 {
 	extern int g_iDPI;
 	return MulDiv(i, g_iDPI, 96);
diff --git a/c/datalistview.cpp b/c/datalistview.cpp
index 532e3a6..a25cc83 100644
--- a/c/datalistview.cpp
+++ b/c/datalistview.cpp
@@ -13,7 +13,7 @@
 
 extern EpisodeListView *g_lpElv;
 
-DataListView::DataListView(HWND hWndParent)
+DataListView::DataListView(const HWND hWndParent)
 	: ListView(hWndParent, (HMENU)IDC_DATALISTVIEW, LVS_NOCOLUMNHEADER)
 {
 	LVCOLUMN lvc;
@@ -31,7 +31,7 @@ DataListView::DataListView(HWND hWndParent)
 	ListView_InsertColumn(m_hWnd, DLVSIVALUE, &lvc);
 }
 
-void DataListView::ShowEpisode(int iEpisode)
+void DataListView::ShowEpisode(const int iEpisode)
 {
 	ListView_DeleteAllItems(m_hWnd);
 
@@ -39,9 +39,9 @@ void DataListView::ShowEpisode(int iEpisode)
 	lviKey.mask = LVIF_TEXT;
 	lviValue.mask = LVIF_TEXT;
 
-	term_t t = PL_new_term_refs(3);
+	const term_t t = PL_new_term_refs(3);
 	if (!PL_put_integer(t,iEpisode)) return;
-	qid_t q = PL_open_query(NULL, PL_Q_NORMAL,
+	const qid_t q = PL_open_query(NULL, PL_Q_NORMAL,
 	    PL_predicate("episode_datum", 3, "episode_data"), t);
 
 	for (int i = 0; PL_next_solution(q); i++) {
diff --git a/c/episodelistview.cpp b/c/episodelistview.cpp
index 01b4c1a..4196062 100644
--- a/c/episodelistview.cpp
+++ b/c/episodelistview.cpp
@@ -13,7 +13,7 @@
 extern DataListView *g_lpDlv;
 int CALLBACK ElvSort(LPARAM, LPARAM, LPARAM);
 
-EpisodeListView::EpisodeListView(HWND hWndParent)
+EpisodeListView::EpisodeListView(const HWND hWndParent)
 	: ListView(hWndParent, (HMENU)IDC_EPISODELISTVIEW, 0)
 {
 	LVCOLUMN lvc;
@@ -45,14 +45,14 @@ void EpisodeListView::DoSort()
 
 void EpisodeListView::EnsureFocusVisible()
 {
-	int iEpFocus = ListView_GetNextItem(m_hWnd, -1, LVNI_FOCUSED);
+	const int iEpFocus = ListView_GetNextItem(m_hWnd, -1, LVNI_FOCUSED);
 	if (iEpFocus == -1) return;
 	ListView_EnsureVisible(m_hWnd, iEpFocus, TRUE);
 }
 
-LRESULT EpisodeListView::HandleNotify(LPARAM lParam)
+LRESULT EpisodeListView::HandleNotify(const LPARAM lParam)
 {
-	LPNMLISTVIEW lpNmLv = (LPNMLISTVIEW)lParam;
+	const LPNMLISTVIEW lpNmLv = (LPNMLISTVIEW)lParam;
 
 	switch (lpNmLv->hdr.code) {
 	case LVN_ITEMCHANGED:	/* Select/focus episode. */
@@ -66,7 +66,7 @@ LRESULT EpisodeListView::HandleNotify(LPARAM lParam)
 		break;
 	case LVN_COLUMNCLICK:	/* Sort by column. */
 	    {
-		int iColumn = lpNmLv->iSubItem+1;
+		const int iColumn = lpNmLv->iSubItem+1;
 		m_iSort = abs(m_iSort) == iColumn? -m_iSort: iColumn;
 		Pl("cfg","set_sort",m_iSort);
 		DoSort();
@@ -75,7 +75,7 @@ LRESULT EpisodeListView::HandleNotify(LPARAM lParam)
 	    }
 	case LVN_KEYDOWN:	/* Navigate episodes by keyboard. */
 	    {
-		LPNMLVKEYDOWN lpNmLvKd = (LPNMLVKEYDOWN)lParam;
+		const LPNMLVKEYDOWN lpNmLvKd = (LPNMLVKEYDOWN)lParam;
 		switch (lpNmLvKd->wVKey) {
 		case VK_LEFT:
 			SelectUnwatched(-1);
@@ -88,7 +88,7 @@ LRESULT EpisodeListView::HandleNotify(LPARAM lParam)
 	    }
 	case NM_CUSTOMDRAW:	/* Make unwatched episodes bold. */
 	    {
-		LPNMLVCUSTOMDRAW lpLvCd = (LPNMLVCUSTOMDRAW)lParam;
+		const LPNMLVCUSTOMDRAW lpLvCd = (LPNMLVCUSTOMDRAW)lParam;
 		switch (lpLvCd->nmcd.dwDrawStage) {
 		case CDDS_PREPAINT:
 			return CDRF_NOTIFYITEMDRAW;
@@ -131,7 +131,7 @@ LRESULT EpisodeListView::HandleNotify(LPARAM lParam)
 	case NM_RCLICK:
 	    {
 		extern HMENU g_hPopupMenu;
-		DWORD dwPos = GetMessagePos();
+		const DWORD dwPos = GetMessagePos();
 		TrackPopupMenu(g_hPopupMenu, TPM_RIGHTBUTTON,
 		    LOWORD(dwPos), HIWORD(dwPos), 0,
 		    m_hWndParent, NULL);
@@ -157,9 +157,9 @@ void EpisodeListView::SaveFocus()
 		Pl("cfg","set_focus",lvi.lParam);
 }
 
-void EpisodeListView::SetTop(int iItem)
+void EpisodeListView::SetTop(const int iItem)
 {
-	int iLast = ListView_GetItemCount(m_hWnd)-1;
+	const int iLast = ListView_GetItemCount(m_hWnd)-1;
 	ListView_EnsureVisible(m_hWnd, iLast, TRUE);
 	ListView_EnsureVisible(m_hWnd, iItem, TRUE);
 }
@@ -237,7 +237,7 @@ void EpisodeListView::SelectUnwatched(int iDir)
 
 void EpisodeListView::ShowFocus()
 {
-	int iEpFocus = ListView_GetNextItem(m_hWnd, -1, LVNI_FOCUSED);
+	const int iEpFocus = ListView_GetNextItem(m_hWnd, -1, LVNI_FOCUSED);
 	if (iEpFocus == -1) return;
 	ListView_EnsureVisible(m_hWnd, iEpFocus, TRUE);
 }
@@ -353,7 +353,7 @@ void EpisodeListView::Update()
 }
 
 /* Update episode name and rating. */
-void EpisodeListView::UpdateItem(LPLVITEM lpLvi)
+void EpisodeListView::UpdateItem(const LPLVITEM lpLvi)
 {
 	TCHAR *tszName;
 	int iRating;
@@ -375,19 +375,18 @@ r:	if (!Pl("episode_data","episode_rating",lpLvi->lParam,&iRating)) {
 	ListView_SetItemText(m_hWnd, lpLvi->iItem, ELVSIRATING, tszRating);
 }
 
-LRESULT CALLBACK EpisodeListView::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+LRESULT CALLBACK EpisodeListView::WndProc(const HWND hWnd, const UINT uMsg,
+    const WPARAM wParam, const LPARAM lParam)
 {
 	switch (uMsg) {
 	case WM_GETDLGCODE:
 	    {
-		LRESULT lResult;
-
 		/* For the episode list view, the Enter key should not
 		 * be handled by the dialog manager, but instead be sent
 		 * along to the main window procedure, so that it may be
 		 * handled by the NM_RETURN case in ElvHandleNotify. */
 
-		lResult = CallWindowProc(m_prevProc, hWnd, uMsg, wParam, lParam);
+		const LRESULT lResult = CallWindowProc(m_prevProc, hWnd, uMsg, wParam, lParam);
 		if (lParam && ((MSG *)lParam)->message == WM_KEYDOWN
 		    && ((MSG *)lParam)->wParam == VK_RETURN)
 			return DLGC_WANTMESSAGE;
@@ -398,7 +397,7 @@ LRESULT CALLBACK EpisodeListView::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, L
 	return ListView::WndProc(hWnd, uMsg, wParam, lParam);
 }
 
-int CALLBACK ElvSort(LPARAM iItem1, LPARAM iItem2, LPARAM lExtra)
+int CALLBACK ElvSort(const LPARAM iItem1, const LPARAM iItem2, const LPARAM lExtra)
 {
 	EpisodeListView *lpElv = (EpisodeListView *)lExtra;
 
@@ -410,7 +409,7 @@ int CALLBACK ElvSort(LPARAM iItem1, LPARAM iItem2, LPARAM lExtra)
 
 	/* abs(m_iSort) is the 1-based index of the column to sort by.
 	 * If m_iSort is negative, the order is descending. */
-	int iOrder = Cmp(lpElv->m_iSort, 0);
+	const int iOrder = Cmp(lpElv->m_iSort, 0);
 
 	switch (abs(lpElv->m_iSort)-1) {
 	case ELVSIEPISODE:
diff --git a/c/listview.cpp b/c/listview.cpp
index 27529e0..5791226 100644
--- a/c/listview.cpp
+++ b/c/listview.cpp
@@ -9,7 +9,7 @@
 extern HFONT g_hfNormal;
 static LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
 
-ListView::ListView(HWND hWndParent, HMENU hMenu, DWORD dwStyle)
+ListView::ListView(const HWND hWndParent, const HMENU hMenu, const DWORD dwStyle)
 {
 	m_hWndParent = hWndParent;
 	m_bHeader = !(dwStyle & LVS_NOCOLUMNHEADER);
@@ -21,13 +21,11 @@ ListView::ListView(HWND hWndParent, HMENU hMenu, DWORD dwStyle)
 	    0, 0, 0, 0,
 	    m_hWndParent, hMenu, GetModuleHandle(NULL), this
 	);
-
 	if (SetProp(m_hWnd, TEXT("this"), (HANDLE)this))
 		m_prevProc = (WNDPROC)SetWindowLongPtr(m_hWnd,
 		    GWLP_WNDPROC, (LONG_PTR)::WndProc);
 
 	ListView_SetExtendedListViewStyle(m_hWnd, LVS_EX_FULLROWSELECT);
-
 	SendMessage(m_hWnd, WM_SETFONT, (WPARAM)g_hfNormal, MAKELPARAM(FALSE, 0));
 }
 
@@ -36,7 +34,7 @@ int ListView::Height(int bHeader)
 {
 	if (bHeader == -1)
 		bHeader = m_bHeader;
-	int iCount = ListView_GetItemCount(m_hWnd);
+	const int iCount = ListView_GetItemCount(m_hWnd);
 	return iCount? Dpi(bHeader? 27: 4)+iCount*Dpi(19): 0;
 }
 
@@ -45,7 +43,7 @@ HWND ListView::Handle() const
 	return m_hWnd;
 }
 
-void ListView::UpdateTheme(BOOL bThemeActive)
+void ListView::UpdateTheme(const BOOL bThemeActive)
 {
 	DWORD dwStyle;
 	LPTSTR tszTheme;
@@ -73,7 +71,8 @@ void ListView::UpdateTheme(BOOL bThemeActive)
 	SendMessage(m_hWnd, WM_UPDATEUISTATE, MAKEWPARAM(wAction, UISF_HIDEFOCUS), 0);
 }
 
-LRESULT CALLBACK ListView::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+LRESULT CALLBACK ListView::WndProc(const HWND hWnd, const UINT uMsg,
+    const WPARAM wParam, const LPARAM lParam)
 {
 	switch (uMsg) {
 	case WM_NOTIFY:
@@ -88,7 +87,8 @@ LRESULT CALLBACK ListView::WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM l
 	return CallWindowProc(m_prevProc, hWnd, uMsg, wParam, lParam);
 }
 
-LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+LRESULT CALLBACK WndProc(const HWND hWnd, const UINT uMsg, const WPARAM wParam,
+    const LPARAM lParam)
 {
 	ListView *lpLv = (ListView *)GetProp(hWnd, TEXT("this"));
 
diff --git a/c/main.cpp b/c/main.cpp
index 64d52f8..73d1e3b 100644
--- a/c/main.cpp
+++ b/c/main.cpp
@@ -28,15 +28,14 @@ int g_bViewWatched = 1;
 int g_bThread = 0;
 int g_iDPI = 96;
 static int g_cxVScroll;
-void OnTerminate(void);
+static void OnTerminate(void);
 static LRESULT CALLBACK CBTProc(int, WPARAM, LPARAM);
 static LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
 static INT_PTR CALLBACK AboutDlgProc(HWND, UINT, WPARAM, LPARAM);
 static HWND CreateStatusBar(HWND, HINSTANCE);
 static void UpdateTheme(void);
 
-int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
-    LPSTR lpCmdLine, INT nCmdShow)
+int WINAPI WinMain(const HINSTANCE hInstance, const HINSTANCE, const LPSTR lpCmdLine, const INT nCmdShow)
 {
 	/* Exit gracefully on uncaught exception. */
 	std::set_terminate(OnTerminate);
@@ -80,8 +79,7 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
 	g_hPopupMenu = LoadMenu(NULL, MAKEINTRESOURCE(IDR_POPUPMENU));
 	g_hPopupMenu = GetSubMenu(g_hPopupMenu, 0);
 
-	WNDCLASSEX wc;
-	memset(&wc, 0, sizeof(WNDCLASSEX));
+	WNDCLASSEX wc = {0};
 	wc.cbSize	 = sizeof(WNDCLASSEX);
 	wc.lpfnWndProc	 = WndProc;
 	wc.hInstance	 = hInstance;
@@ -97,10 +95,8 @@ int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
 	/* Create window. Note that a CBT hook is used to initialize
 	 * important global variables before any messages are sent to
 	 * the new window. */
-	HHOOK hHook;
-	HWND hWnd;
-	hHook = SetWindowsHookEx(WH_CBT, CBTProc, 0, GetCurrentThreadId());
-	hWnd = CreateWindowEx(
+	const HHOOK hHook = SetWindowsHookEx(WH_CBT, CBTProc, 0, GetCurrentThreadId());
+	const HWND hWnd = CreateWindowEx(
 	    0,
 	    TEXT("Episode Browser"),
 	    TEXT("Episode Browser"),
@@ -133,7 +129,7 @@ void OnTerminate()
 {
 	try {
 		std::rethrow_exception(std::current_exception());
-        } catch (term_t &t) {
+        } catch (const term_t &t) {
 		TCHAR *tsz;
 		if (PL_get_tchars(t, &tsz, CVT_WRITE)) {
 			MessageBox(NULL, tsz, TEXT("Fatal Error"), MB_ICONERROR);
@@ -178,7 +174,7 @@ static LRESULT CALLBACK CBTProc(int nCode, WPARAM wParam, LPARAM lParam)
 	return 0;
 }
 
-LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+LRESULT CALLBACK WndProc(const HWND hWnd, const UINT uMsg, const WPARAM wParam, LPARAM lParam)
 {
 	switch (uMsg) {
 	case WM_CREATE:
@@ -200,11 +196,9 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 		DestroyWindow(hWnd);
 		break;
 	case WM_DESTROY:
-	    {
 		g_lpElv->SaveFocus();
 		PostQuitMessage(0);
 		break;
-	    }
 	case WM_SIZE:
 		SendMessage(g_hWndStatus, WM_SIZE, wParam, lParam);
 		UpdateLayout();
@@ -221,7 +215,7 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 		break;
 	case 0x02E0: /* WM_DPICHANGED */
 	    {
-		LPRECT lpr = (LPRECT)lParam;
+		const LPRECT lpr = (LPRECT)lParam;
 		g_iDPI = HIWORD(wParam);
 		SetWindowPos(hWnd, NULL,
 		    lpr->left, lpr->top,
@@ -302,7 +296,6 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 			);
 			break;
 		case IDM_VIEW_WATCHED:
-		    {
 			CheckMenuItem(GetMenu(hWnd), IDM_VIEW_WATCHED,
 			    g_bViewWatched? MF_UNCHECKED: MF_CHECKED);
 			g_bViewWatched = !g_bViewWatched;
@@ -310,9 +303,7 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 			g_lpElv->Update();
 			g_lpElv->EnsureFocusVisible();
 			break;
-		    }
 		case IDM_VIEW_TV_ORIGINAL:
-		    {
 			CheckMenuItem(GetMenu(hWnd), IDM_VIEW_TV_ORIGINAL,
 			    g_bViewTVOriginal? MF_UNCHECKED: MF_CHECKED);
 			g_bViewTVOriginal = !g_bViewTVOriginal;
@@ -320,16 +311,13 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 			g_lpElv->Update();
 			g_lpElv->EnsureFocusVisible();
 			break;
-		    }
 		case IDM_VIEW_OTHERS:	/* Show/hide other screenwriters. */
-		    {
-			int iEpFocus;
 			if (g_szLimitScreenwriter[0]) {
 				CheckMenuItem(GetMenu(hWnd), IDM_VIEW_OTHERS,
 				    MF_CHECKED);
 				g_szLimitScreenwriter[0] = 0;
 			} else {
-				iEpFocus = ListView_GetNextItem(g_lpElv->Handle(), -1, LVNI_FOCUSED);
+				const int iEpFocus = ListView_GetNextItem(g_lpElv->Handle(), -1, LVNI_FOCUSED);
 				if (iEpFocus == -1) break;
 
 				LVITEM lvi;
@@ -349,7 +337,6 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 			g_lpElv->Update();
 			g_lpElv->EnsureFocusVisible();
 			break;
-		    }
 		case IDM_WATCH_LOCALLY:
 		case IDM_WATCH_ONLINE:
 		case IDM_TOGGLE:
@@ -469,7 +456,7 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
 	return 0;
 }
 
-INT_PTR CALLBACK AboutDlgProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
+INT_PTR CALLBACK AboutDlgProc(const HWND hWnd, const UINT uMsg, const WPARAM wParam, const LPARAM lParam)
 {
 	switch (uMsg) {
 	case WM_CLOSE:
@@ -489,9 +476,9 @@ INT_PTR CALLBACK AboutDlgProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam
 	return TRUE;
 }
 
-HWND CreateStatusBar(HWND hWndParent, HINSTANCE hInstance)
+HWND CreateStatusBar(const HWND hWndParent, const HINSTANCE hInstance)
 {
-	HWND hWnd = CreateWindowEx(
+	return CreateWindowEx(
 	    0,
 	    STATUSCLASSNAME,
 	    (LPCTSTR) NULL,
@@ -502,7 +489,6 @@ HWND CreateStatusBar(HWND hWndParent, HINSTANCE hInstance)
 	    hInstance,
 	    NULL
 	);
-	return hWnd;
 }
 
 /***/
@@ -537,7 +523,7 @@ void UpdateLayout()
 	SendMessage(g_lpDlv->Handle(), WM_SETREDRAW, TRUE, 0);
 
 	/* Resize status bar parts. */
-	int aParts[] = {rc.right-Dpi(55), rc.right};
+	const int aParts[] = {rc.right-Dpi(55), rc.right};
 	SendMessage(g_hWndStatus, SB_SETPARTS, (WPARAM)sizeof(aParts), (LPARAM)aParts);
 }
 
@@ -545,7 +531,7 @@ void UpdateLayout()
 void UpdateTheme()
 {
 	if (!g_bThemes) return;
-	BOOL bThemeActive = IsThemeActive();
+	const int bThemeActive = IsThemeActive();
 	g_lpDlv->UpdateTheme(bThemeActive);
 	g_lpElv->UpdateTheme(bThemeActive);
 }
diff --git a/c/pl.cpp b/c/pl.cpp
index 21253ba..307fc1e 100644
--- a/c/pl.cpp
+++ b/c/pl.cpp
@@ -3,7 +3,7 @@
 
 #include "pl.h"
 
-Query::Query(module_t ctx, predicate_t p, term_t t0)
+Query::Query(const module_t ctx, const predicate_t p, const term_t t0)
 {
 	m_q = PL_open_query(ctx, PL_Q_CATCH_EXCEPTION, p, t0);
 }
@@ -16,25 +16,25 @@ Query::~Query()
 int Query::Cut()
 {
 	if (PL_cut_query(m_q)) return 1;
-	if (term_t t = PL_exception(m_q)) throw t;
+	if (const term_t t = PL_exception(m_q)) throw t;
 	return 0;
 }
 
 int Query::Close()
 {
 	if (PL_close_query(m_q)) return 1;
-	if (term_t t = PL_exception(m_q)) throw t;
+	if (const term_t t = PL_exception(m_q)) throw t;
 	return 0;
 }
 
 int Query::NextSolution()
 {
 	if (PL_next_solution(m_q)) return 1;
-	if (term_t t = PL_exception(m_q)) throw t;
+	if (const term_t t = PL_exception(m_q)) throw t;
 	return 0;
 }
 
-int PL_get_tchars(term_t t, TCHAR **lpTsz, int iFlags)
+int PL_get_tchars(const term_t t, TCHAR **lpTsz, const int iFlags)
 {
 #ifdef UNICODE
 	size_t len;
@@ -50,7 +50,7 @@ int PL_get_tchars(term_t t, TCHAR **lpTsz, int iFlags)
 
 int Plx(const char *szMod, const char *szPred)
 {
-	term_t t = PL_new_term_refs(0);
+	const term_t t = PL_new_term_refs(0);
 	Query q(NULL, PL_predicate(szPred, 0, szMod), t);
 	return q.NextSolution();
 }
diff --git a/c/pl.h b/c/pl.h
index e1dbea7..9f40676 100644
--- a/c/pl.h
+++ b/c/pl.h
@@ -19,61 +19,61 @@ private:
 };
 
 /* Polymorphic aliases for PL_put_*, PL_get_*. */
-inline int PlPut(term_t t, int x) { return PL_put_integer(t, x); }
-inline int PlPut(term_t t, long x) { return PL_put_integer(t, x); }
-inline int PlPut(term_t t, long long x) { return PL_put_integer(t, x); }
-inline int PlPut(term_t t, atom_t x) { return PL_put_atom(t, x); }
-inline int PlPut(term_t t, char *x) { return PL_put_atom(t, PL_new_atom(x)); }
-inline int PlPut(term_t t, const char *x) { return PL_put_atom(t, PL_new_atom(x)); }
-inline int PlPut(term_t t, wchar_t *x) { return PL_put_atom(t, PL_new_atom_wchars(-1, x)); }
-inline int PlPut(term_t t, const wchar_t *x) { return PL_put_atom(t, PL_new_atom_wchars(-1, x)); }
-inline int PlPut(term_t, int *) { return -1; }
-inline int PlPut(term_t, long *) { return -1; }
-inline int PlPut(term_t, long long *) { return -1; }
-inline int PlPut(term_t, atom_t *) { return -1; }
-inline int PlPut(term_t, char **) { return -1; }
-inline int PlPut(term_t, wchar_t **) { return -1; }
+inline int PlPut(const term_t t, const int x) { return PL_put_integer(t, x); }
+inline int PlPut(const term_t t, const long x) { return PL_put_integer(t, x); }
+inline int PlPut(const term_t t, const long long x) { return PL_put_integer(t, x); }
+inline int PlPut(const term_t t, const atom_t x) { return PL_put_atom(t, x); }
+inline int PlPut(const term_t t, char *x) { return PL_put_atom(t, PL_new_atom(x)); }
+inline int PlPut(const term_t t, const char *x) { return PL_put_atom(t, PL_new_atom(x)); }
+inline int PlPut(const term_t t, wchar_t *x) { return PL_put_atom(t, PL_new_atom_wchars(-1, x)); }
+inline int PlPut(const term_t t, const wchar_t *x) { return PL_put_atom(t, PL_new_atom_wchars(-1, x)); }
+inline int PlPut(const term_t, int *) { return -1; }
+inline int PlPut(const term_t, long *) { return -1; }
+inline int PlPut(const term_t, long long *) { return -1; }
+inline int PlPut(const term_t, atom_t *) { return -1; }
+inline int PlPut(const term_t, char **) { return -1; }
+inline int PlPut(const term_t, wchar_t **) { return -1; }
 
-inline int PlGet(term_t, int) { return -1; }
-inline int PlGet(term_t, long) { return -1; }
-inline int PlGet(term_t, long long) { return -1; }
-inline int PlGet(term_t, atom_t) { return -1; }
-inline int PlGet(term_t, char*) { return -1; }
-inline int PlGet(term_t, const char *) { return -1; }
-inline int PlGet(term_t t, int *x) { return PL_get_integer(t, x); }
-inline int PlGet(term_t t, long *x) { return PL_get_long(t, x); }
-inline int PlGet(term_t t, long long *x) { return PL_get_int64(t, x); }
-inline int PlGet(term_t t, atom_t *x) { return PL_get_atom(t, x); }
-inline int PlGet(term_t t, char **x) { return PL_get_atom_chars(t, x); }
-inline int PlGet(term_t t, wchar_t **x)
+inline int PlGet(const term_t, const int) { return -1; }
+inline int PlGet(const term_t, const long) { return -1; }
+inline int PlGet(const term_t, const long long) { return -1; }
+inline int PlGet(const term_t, const atom_t) { return -1; }
+inline int PlGet(const term_t, char*) { return -1; }
+inline int PlGet(const term_t, const char *) { return -1; }
+inline int PlGet(const term_t t, int *x) { return PL_get_integer(t, x); }
+inline int PlGet(const term_t t, long *x) { return PL_get_long(t, x); }
+inline int PlGet(const term_t t, long long *x) { return PL_get_int64(t, x); }
+inline int PlGet(const term_t t, atom_t *x) { return PL_get_atom(t, x); }
+inline int PlGet(const term_t t, char **x) { return PL_get_atom_chars(t, x); }
+inline int PlGet(const term_t t, wchar_t **x)
 {
 	atom_t a;
-	size_t siz;
+	size_t len;
 	if (!PL_get_atom(t, &a)) return 0;
-	*x = (wchar_t *)PL_atom_wchars(a, &siz);
+	*x = (wchar_t *)PL_atom_wchars(a, &len);
 	return *x != NULL;
 }
 
 /* Helper templates for Plx, Pl. */
 template <typename T>
-int PlPutv(term_t t, T arg) { return PlPut(t, arg); }
+int PlPutv(const term_t t, T arg) { return PlPut(t, arg); }
 template <typename T, typename ...R>
-int PlPutv(term_t t, T arg, R... rest) { return PlPut(t, arg)? PlPutv(t+1, rest...): 0; }
+int PlPutv(const term_t t, T arg, R... rest) { return PlPut(t, arg)? PlPutv(t+1, rest...): 0; }
 template <typename T>
-int PlGetv(term_t t, T arg) { return PlGet(t, arg); }
+int PlGetv(const term_t t, T arg) { return PlGet(t, arg); }
 template <typename T, typename ...R>
-int PlGetv(term_t t, T arg, R... rest) { return PlGet(t, arg)? PlGetv(t+1, rest...): 0; }
+int PlGetv(const term_t t, T arg, R... rest) { return PlGet(t, arg)? PlGetv(t+1, rest...): 0; }
 template <typename T>
-int Countv(int i, T arg) { return i+1; }
+int Countv(const int i, T arg) { return i+1; }
 template <typename T, typename ...R>
-int Countv(int i, T arg, R... rest) { return Countv(i+1, rest...); }
+int Countv(const int i, T arg, R... rest) { return Countv(i+1, rest...); }
 
 /* Call Prolog predicate, propagating Prolog exceptions. */
 template <typename ...T>
 int Plx(const char *szMod, const char *szPred, T... args)
 {
-	int iArity = Countv(0, args...);
-	term_t t = PL_new_term_refs(iArity);
+	const int iArity = Countv(0, args...);
+	const term_t t = PL_new_term_refs(iArity);
 	if (!PlPutv(t, args...)) return 0;
 	Query q(NULL, PL_predicate(szPred, iArity, szMod), t);
 	if (!q.NextSolution()) return 0;