Uses SNPRINT macro where possible. Otherwise uses #define for format.

runtime/vm/os_macos.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_OS_MACOS)
 
 #include "vm/os.h"
 
 #include <errno.h>  // NOLINT
@@ skipping 187 matching lines @@
 
 int OS::SNPrint(char* str, size_t size, const char* format, ...) {
   va_list args;
   va_start(args, format);
   int retval = VSNPrint(str, size, format, args);
   va_end(args);
   return retval;
 }
 
 
+char* OS::SNCreate(Zone* zone, const char* format, ...) {
+  va_list args;
+  va_start(args, format);
+
+  // Measure.
+  va_list measure_args;
+  va_copy(measure_args, args);
+  intptr_t len = VSNPrint(NULL, 0, format, measure_args);
+  va_end(measure_args);
+
+  char* buffer;
+  if (zone) {
+    buffer = zone->Alloc<char>(len + 1);
+  } else {
+    buffer = reinterpret_cast<char*>(malloc(len + 1));
+  }
+  ASSERT(buffer != NULL);
+
+  // Print.
+  va_list print_args;
+  va_copy(print_args, args);
+  VSNPrint(buffer, len + 1, format, print_args);
+  va_end(print_args);
+  va_end(args);
+  return buffer;
+}
+
+
 int OS::VSNPrint(char* str, size_t size, const char* format, va_list args) {
   int retval = vsnprintf(str, size, format, args);
   if (retval < 0) {
     FATAL1("Fatal error in OS::VSNPrint with format '%s'", format);
   }
   return retval;
 }
 
 
 bool OS::StringToInt64(const char* str, int64_t* value) {
@@ skipping 46 matching lines @@
 }
 
 
 void OS::Exit(int code) {
   exit(code);
 }
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)