From c8941cccb592a58b4bfaff97abf114fecab64edc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Ho=C5=99e=C5=88ovsk=C3=BD?=
 <martin.horenovsky@gmail.com>
Date: Sun, 8 Jul 2018 13:35:40 +0200
Subject: [PATCH] Add an example on providing streams with
 `CATCH_CONFIG_NOSTDOUT`

Related to #1037
Closes #1290
---
 docs/list-of-examples.md           |  2 +-
 examples/231-Cfg-OutputStreams.cpp | 49 ++++++++++++++++++++++++++++++
 examples/CMakeLists.txt            |  1 +
 3 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100644 examples/231-Cfg-OutputStreams.cpp

diff --git a/docs/list-of-examples.md b/docs/list-of-examples.md
index 81f5a903..e1725a86 100644
--- a/docs/list-of-examples.md
+++ b/docs/list-of-examples.md
@@ -10,7 +10,7 @@
 - Fixture: [Class-based fixtures](../examples/110-Fix-ClassFixture.cpp)
 - BDD: [SCENARIO, GIVEN, WHEN, THEN](../examples/120-Bdd-ScenarioGivenWhenThen.cpp)
 - Listener: [Listeners](../examples/210-Evt-EventListeners.cpp)
-
+- Configuration: [Provide your own output streams](../examples/231-Cfg-OutputStreams.cpp)
 
 ## Planned
 
diff --git a/examples/231-Cfg-OutputStreams.cpp b/examples/231-Cfg-OutputStreams.cpp
new file mode 100644
index 00000000..efa99971
--- /dev/null
+++ b/examples/231-Cfg-OutputStreams.cpp
@@ -0,0 +1,49 @@
+// 231-Cfg-OutputStreams.cpp
+// Show how to replace the streams with a simple custom made streambuf.
+
+// Note that this reimplementation _does not_ follow `std::cerr`
+// semantic, because it buffers the output. For most uses however,
+// there is no important difference between having `std::cerr` buffered
+// or unbuffered.
+
+#define CATCH_CONFIG_NOSTDOUT
+#define CATCH_CONFIG_MAIN
+#include <catch2/catch.hpp>
+
+class out_buff : public std::stringbuf {
+    std::FILE* m_stream;
+public:
+    out_buff(std::FILE* stream) :m_stream(stream) {}
+    ~out_buff() { pubsync(); }
+    int sync() {
+        int ret = 0;
+        for (unsigned char c : str()) {
+            if (putc(c, m_stream) == EOF) {
+                ret = -1;
+                break;
+            }
+        }
+        // Reset the buffer to avoid printing it multiple times
+        str("");
+        return ret;
+    }
+};
+
+namespace Catch {
+    std::ostream& cout() {
+        static std::ostream ret(new out_buff(stdout));
+        return ret;
+    }
+    std::ostream& clog() {
+        static std::ostream ret(new out_buff(stderr));
+        return ret;
+    }
+    std::ostream& cerr() {
+        return clog();
+    }
+}
+
+
+TEST_CASE("This binary uses putc to write out output", "[compilation-only]") {
+    SUCCEED("Nothing to test.");
+}
diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 72d04763..5c471b4f 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -17,6 +17,7 @@ set( HEADER_DIR   ${CATCH_DIR}/single_include )
 
 set( SOURCES_SINGLE_FILE
     010-TestCase.cpp
+    231-Cfg-OutputStreams.cpp
 )
 
 # multiple-file modules: