Add support for line buffering

2024-01-27 08:57:21 -08:00
parent 6f260455aa
commit 6435b169ec
2 changed files with 24 additions and 0 deletions
@@ -1752,6 +1752,21 @@ TEST(format_test, big_print) {
  EXPECT_WRITE(stdout, big_print(), std::string(count, 'x'));
 }

+// Windows CRT implements _IOLBF incorrectly (full buffering).
+#if FMT_USE_FCNTL && !defined(_WIN32)
+TEST(format_test, line_buffering) {
+  auto pipe = fmt::pipe();
+  auto read_end = pipe.read_end.fdopen("r");
+  auto write_end = pipe.write_end.fdopen("w");
+  setvbuf(write_end.get(), nullptr, _IOLBF, 4096);
+  write_end.print("42\n");
+  int n = 0;
+  int result = fscanf(read_end.get(), "%d", &n);
+  (void)result;
+  EXPECT_EQ(n, 42);
+}
+#endif
+
 TEST(format_test, variadic) {
  EXPECT_EQ(fmt::format("{}c{}", "ab", 1), "abc1");
 }