Added uiMultilineEntry, wrote it on GTK+, and wrote the uiQueueMain() test. It works on Unix.

test/queuemaintest.cpp

@@ -0,0 +1,89 @@
+// 6 december 2015
+#include <thread>
+#include <chrono>
+#include <mutex>
+#include <condition_variable>
+#include <string.h>
+#include <stdlib.h>
+#include <time.h>
+#include "../ui.h"
+using namespace std;
+
+uiMultilineEntry *e;
+condition_variable cv;
+mutex m;
+unique_lock<mutex> ourlock(m);
+thread *timeThread;
+
+void sayTime(void *data)
+{
+	char *s = (char *) data;
+
+	uiMultilineEntryAppend(e, s);
+	delete s;
+}
+
+void threadproc(void)
+{
+	while (cv.wait_for(ourlock, chrono::seconds(1)) == cv_status::timeout) {
+		time_t t;
+		char *base;
+		char *s;
+
+		t = time(NULL);
+		base = ctime(&t);
+		s = new char[strlen(base) + 1];
+		strcpy(s, base);
+		uiQueueMain(sayTime, s);
+	}
+}
+
+int onClosing(uiWindow *w, void *data)
+{
+	cv.notify_all();
+	// C++ throws a hissy fit if you don't do this
+	// we might as well, to ensure no uiQueueMain() gets in after uiQuit()
+	timeThread->join();
+	uiQuit();
+	return 1;
+}
+
+void saySomething(uiButton *b, void *data)
+{
+	uiMultilineEntryAppend(e, "Saying something\n");
+}
+
+int main(void)
+{
+	uiInitOptions o;
+	uiWindow *w;
+	uiBox *b;
+	uiButton *btn;
+
+	memset(&o, 0, sizeof (uiInitOptions));
+	if (uiInit(&o) != NULL)
+		abort();
+
+	w = uiNewWindow("Hello", 320, 240, 0);
+	uiWindowSetMargined(w, 1);
+
+	b = uiNewVerticalBox();
+	uiBoxSetPadded(b, 1);
+	uiWindowSetChild(w, uiControl(b));
+
+	e = uiNewMultilineEntry();
+	uiMultilineEntrySetReadOnly(e, 1);
+
+	btn = uiNewButton("Say Something");
+	uiButtonOnClicked(btn, saySomething, NULL);
+	uiBoxAppend(b, uiControl(btn), 0);
+
+	uiBoxAppend(b, uiControl(e), 1);
+
+	timeThread = new thread(threadproc);
+
+	uiWindowOnClosing(w, onClosing, NULL);
+	uiControlShow(uiControl(w));
+	uiMain();
+	return 0;
+}

ui.h

@@ -229,6 +229,21 @@ _UI_EXTERN uiDateTimePicker *uiNewDateTimePicker(void);
 _UI_EXTERN uiDateTimePicker *uiNewDatePicker(void);
 _UI_EXTERN uiDateTimePicker *uiNewTimePicker(void);
 
+// TODO merge with uiEntry? some things can't be shared (for instance, the future Invalid()
+// TODO how are line endings converted?
+// TODO provide a facility for allowing horizontal scrolling
+// TODO provide a facility for entering tab stops?
+typedef struct uiMultilineEntry uiMultilineEntry;
+_UI_EXTERN uintmax_t uiMultilineEntryType(void);
+#define uiMultilineEntry(this) ((uiMultilineEntry *) uiIsA((this), uiMultilineEntryType(), 1))
+_UI_EXTERN char *uiMultilineEntryText(uiMultilineEntry *e);
+_UI_EXTERN void uiMultilineEntrySetText(uiMultilineEntry *e, const char *text);
+_UI_EXTERN void uiMultilineEntryAppend(uiMultilineEntry *e, const char *text);
+_UI_EXTERN void uiMultilineEntryOnChanged(uiMultilineEntry *e, void (*f)(uiMultilineEntry *e, void *data), void *data);
+_UI_EXTERN int uiMultilineEntryReadOnly(uiMultilineEntry *e);
+_UI_EXTERN void uiMultilineEntrySetReadOnly(uiMultilineEntry *e, int readonly);
+_UI_EXTERN uiMultilineEntry *uiNewMultilineEntry(void);
+
 typedef struct uiMenu uiMenu;
 typedef struct uiMenuItem uiMenuItem;
 _UI_EXTERN uintmax_t uiMenuType(void);

unix/GNUmakeinc.mk

@@ -16,6 +16,7 @@ CFILES += \
 	unix/label.c \
 	unix/main.c \
 	unix/menu.c \
+	unix/multilineentry.c \
 	unix/progressbar.c \
 	unix/radiobuttons.c \
 	unix/separator.c \

unix/multilineentry.c

@@ -0,0 +1,117 @@
+// 6 december 2015
+#include "uipriv_unix.h"
+
+// TODO: ensure this can only be used to enter plain text
+
+struct uiMultilineEntry {
+	uiUnixControl c;
+	GtkWidget *widget;
+	GtkContainer *scontainer;
+	GtkScrolledWindow *sw;
+	GtkWidget *textviewWidget;
+	GtkTextView *textview;
+	GtkTextBuffer *textbuf;
+	void (*onChanged)(uiMultilineEntry *, void *);
+	void *onChangedData;
+	gulong onChangedSignal;
+};
+
+uiUnixDefineControl(
+	uiMultilineEntry,						// type name
+	uiMultilineEntryType						// type function
+)
+
+static void onChanged(GtkTextBuffer *textbuf, gpointer data)
+{
+	uiMultilineEntry *e = uiMultilineEntry(data);
+
+	(*(e->onChanged))(e, e->onChangedData);
+}
+
+static void defaultOnChanged(uiMultilineEntry *e, void *data)
+{
+	// do nothing
+}
+
+char *uiMultilineEntryText(uiMultilineEntry *e)
+{
+	GtkTextIter start, end;
+	char *tret, *out;
+
+	gtk_text_buffer_get_start_iter(e->textbuf, &start);
+	gtk_text_buffer_get_end_iter(e->textbuf, &end);
+	tret = gtk_text_buffer_get_text(e->textbuf, &start, &end, TRUE);
+	// theoretically we could just return tret because uiUnixStrdupText() is just g_strdup(), but if that ever changes we can't, so let's do it this way to be safe
+	out = uiUnixStrdupText(tret);
+	g_free(tret);
+	return out;
+}
+
+void uiMultilineEntrySetText(uiMultilineEntry *e, const char *text)
+{
+	// TODO does this send a changed signal?
+	gtk_text_buffer_set_text(e->textbuf, text, -1);
+}
+
+// TODO scroll to end?
+void uiMultilineEntryAppend(uiMultilineEntry *e, const char *text)
+{
+	GtkTextIter end;
+
+	gtk_text_buffer_get_end_iter(e->textbuf, &end);
+	// TODO does this send a changed signal?
+	gtk_text_buffer_insert(e->textbuf, &end, text, -1);
+}
+
+void uiMultilineEntryOnChanged(uiMultilineEntry *e, void (*f)(uiMultilineEntry *e, void *data), void *data)
+{
+	e->onChanged = f;
+	e->onChangedData = data;
+}
+
+int uiMultilineEntryReadOnly(uiMultilineEntry *e)
+{
+	return gtk_text_view_get_editable(e->textview) == FALSE;
+}
+
+void uiMultilineEntrySetReadOnly(uiMultilineEntry *e, int readonly)
+{
+	gboolean editable;
+
+	editable = TRUE;
+	if (readonly)
+		editable = FALSE;
+	gtk_text_view_set_editable(e->textview, editable);
+}
+
+uiMultilineEntry *uiNewMultilineEntry(void)
+{
+	uiMultilineEntry *e;
+
+	e = (uiMultilineEntry *) uiNewControl(uiMultilineEntryType());
+
+	e->widget = gtk_scrolled_window_new(NULL, NULL);
+	e->scontainer = GTK_CONTAINER(e->widget);
+	e->sw = GTK_SCROLLED_WINDOW(e->widget);
+	gtk_scrolled_window_set_policy(e->sw,
+		GTK_POLICY_NEVER,
+		GTK_POLICY_AUTOMATIC);
+	gtk_scrolled_window_set_shadow_type(e->sw, GTK_SHADOW_IN);
+
+	e->textviewWidget = gtk_text_view_new();
+	e->textview = GTK_TEXT_VIEW(e->textviewWidget);
+	gtk_text_view_set_wrap_mode(e->textview, GTK_WRAP_WORD);
+
+	gtk_container_add(e->scontainer, e->textviewWidget);
+	// and make the text view visible; only the scrolled window's visibility is controlled by libui
+	gtk_widget_show(e->textviewWidget);
+
+	e->textbuf = gtk_text_view_get_buffer(e->textview);
+
+	e->onChangedSignal = g_signal_connect(e->textbuf, "changed", G_CALLBACK(onChanged), e);
+	uiMultilineEntryOnChanged(e, defaultOnChanged, NULL);
+
+	uiUnixFinishNewControl(e, uiMultilineEntry);
+
+	return e;
+}