Add versions of emscripten_out/err/dbg that take an explicit string length (#19492)

Author: sbc100

src/library.js

@@ -3391,15 +3391,24 @@ mergeInto(LibraryManager.library, {
   emscripten_out: function(str) {
     out(UTF8ToString(str));
   },
+  emscripten_outn: function(str, len) {
+    out(UTF8ToString(str, len));
+  },
 
   emscripten_err: function(str) {
     err(UTF8ToString(str));
   },
+  emscripten_errn: function(str, len) {
+    err(UTF8ToString(str, len));
+  },
 
 #if ASSERTIONS || RUNTIME_DEBUG
   emscripten_dbg: function(str) {
     dbg(UTF8ToString(str));
   },
+  emscripten_dbgn: function(str, len) {
+    dbg(UTF8ToString(str, len));
+  },
 #endif
 
   // Use program_invocation_short_name and program_invocation_name in compiled

src/library_sigs.js

@@ -588,13 +588,15 @@ sigs = {
   emscripten_current_thread_is_wasm_worker__sig: 'i',
   emscripten_date_now__sig: 'd',
   emscripten_dbg__sig: 'vp',
+  emscripten_dbgn__sig: 'vpp',
   emscripten_debugger__sig: 'v',
   emscripten_destroy_audio_context__sig: 'vi',
   emscripten_destroy_web_audio_node__sig: 'vi',
   emscripten_destroy_worker__sig: 'vi',
   emscripten_dlopen__sig: 'vpippp',
   emscripten_enter_soft_fullscreen__sig: 'ipp',
   emscripten_err__sig: 'vp',
+  emscripten_errn__sig: 'vpp',
   emscripten_exit_fullscreen__sig: 'i',
   emscripten_exit_pointerlock__sig: 'i',
   emscripten_exit_soft_fullscreen__sig: 'i',
@@ -677,6 +679,7 @@ sigs = {
   emscripten_notify_memory_growth__sig: 'vp',
   emscripten_num_logical_cores__sig: 'i',
   emscripten_out__sig: 'vp',
+  emscripten_outn__sig: 'vpp',
   emscripten_pause_main_loop__sig: 'v',
   emscripten_pc_get_column__sig: 'ip',
   emscripten_pc_get_file__sig: 'pp',

system/include/emscripten/console.h

@@ -5,6 +5,8 @@
  * found in the LICENSE file.
  */
 
+#include <stddef.h>  // for size_t
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -26,6 +28,12 @@ void emscripten_out(const char *utf8String __attribute__((nonnull)));
 void emscripten_err(const char *utf8String __attribute__((nonnull)));
 void emscripten_dbg(const char *utf8String __attribute__((nonnull)));
 
+// Same as above but only with the legnth of string specified by the second
+// argument.  This allows for non-NULL-terminated strings to be passed.
+void emscripten_outn(const char *utf8String __attribute__((nonnull)), size_t len);
+void emscripten_errn(const char *utf8String __attribute__((nonnull)), size_t len);
+void emscripten_dbgn(const char *utf8String __attribute__((nonnull)), size_t len);
+
 // Legacy/internal names for the above
 #define _emscripten_out(x) emscripten_out(x)
 #define _emscripten_err(x) emscripten_err(x)

test/other/test_dbg.c

@@ -13,6 +13,7 @@ int main() {
 #ifndef NDEBUG
   // This symbol is only available in debug builds (i.e. -sASSERTIONS)
   emscripten_dbg("native dbg message");
+  emscripten_dbgn("hello world!", 5);
   emscripten_dbgf("formatted: %d", 42);
 #endif
   return 0;

test/test_other.py

@@ -13158,6 +13158,7 @@ def test_dbg(self):
 w:0,t:0x[0-9a-fA-F]+: done init
 hello, world!
 w:0,t:0x[0-9a-fA-F]+: native dbg message
+w:0,t:0x[0-9a-fA-F]+: hello
 w:0,t:0x[0-9a-fA-F]+: formatted: 42
 '''
     self.emcc_args.append('--pre-js=pre.js')