Add a Print overload that writes to a file.

format.h

@@ -1062,7 +1062,6 @@ class BasicWriter {
    */
   BasicFormatter<Char> Format(StringRef format);
 
-  // TODO: ArgInfo should be made public for this to be usable
   inline void VFormat(BasicStringRef<Char> format,
       std::size_t num_args, const ArgInfo *args) {
     FormatParser().Format(*this, format, num_args, args);
@@ -1619,12 +1618,19 @@ class FileSink {
 // Formats a string and prints it to stdout.
 // Example:
 //   Print("Elapsed time: {0:.2f} seconds") << 1.23;
-// TODO: wchar overload
 inline Formatter<FileSink> Print(StringRef format) {
   Formatter<FileSink> f(format, FileSink(stdout));
   return f;
 }
 
+// Formats a string and prints it to a file.
+// Example:
+//   Print(stderr, "Don't {}!") << "panic";
+inline Formatter<FileSink> Print(std::FILE *file, StringRef format) {
+  Formatter<FileSink> f(format, FileSink(file));
+  return f;
+}
+
 enum Color { BLACK, RED, GREEN, YELLOW, BLUE, MAGENTA, CYAN, WHITE };
 
 /**
@@ -1680,6 +1686,13 @@ void Print(StringRef format, const Args & ... args) {
   std::fwrite(w.data(), 1, w.size(), stdout);
 }
 
+template<typename... Args>
+void Print(std::FILE *f, StringRef format, const Args & ... args) {
+  Writer w;
+  w.Format(format, args...);
+  std::fwrite(w.data(), 1, w.size(), f);
+}
+
 #endif  // FMT_USE_VARIADIC_TEMPLATES && FMT_USE_RVALUE_REFERENCES
 
 /**

test/format-test.cc

@@ -1833,6 +1833,20 @@ TEST(FormatIntTest, FormatDec) {
 
 #if FMT_USE_FILE_DESCRIPTORS
 
+TEST(FormatTest, Print) {
+  EXPECT_WRITE(stdout, fmt::Print("Don't {}!") << "panic", "Don't panic!");
+  EXPECT_WRITE(stderr,
+      fmt::Print(stderr, "Don't {}!") << "panic", "Don't panic!");
+}
+
+#if FMT_USE_VARIADIC_TEMPLATES && FMT_USE_RVALUE_REFERENCES
+TEST(FormatTest, PrintVariadic) {
+  EXPECT_WRITE(stdout, fmt::Print("Don't {}!", "panic"), "Don't panic!");
+  EXPECT_WRITE(stderr,
+      fmt::Print(stderr, "Don't {}!", "panic"), "Don't panic!");
+}
+#endif  // FMT_USE_VARIADIC_TEMPLATES
+
 TEST(FormatTest, PrintColored) {
   EXPECT_WRITE(stdout, fmt::PrintColored(fmt::RED, "Hello, {}!\n") << "world",
       "\x1b[31mHello, world!\n\x1b[0m");
@@ -1842,8 +1856,9 @@ TEST(FormatTest, PrintColored) {
 
 #if FMT_USE_VARIADIC_TEMPLATES && FMT_USE_RVALUE_REFERENCES
 TEST(FormatTest, Variadic) {
-  EXPECT_EQ("Hello, world!1", str(Format("Hello, {}!{}", "world", 1)));
-  EXPECT_EQ(L"Hello, world!1", str(Format(L"Hello, {}!{}", L"world", 1)));
+  EXPECT_EQ("abc1", str(Format("{}c{}", "ab", 1)));
+  EXPECT_EQ(L"abc1", str(Format(L"{}c{}", L"ab", 1)));
+  EXPECT_WRITE(stdout, fmt::Print("So {}!", "variadic"), "So variadic!");
 }
 #endif  // FMT_USE_VARIADIC_TEMPLATES