From 2eb363297b24cd71a68ccfb20ff755430f17e60f Mon Sep 17 00:00:00 2001
From: frank-weinberg <34135287+frank-weinberg@users.noreply.github.com>
Date: Fri, 19 Jan 2024 17:14:48 +0100
Subject: [PATCH] Fix custom formatter example (#3820)

Add a return type declaration so the example builds when the formatter is used in a different compilation unit than it's implemented.
---
 doc/api.rst | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/doc/api.rst b/doc/api.rst
index 7b16b0644321..ca193bda3978 100644
--- a/doc/api.rst
+++ b/doc/api.rst
@@ -139,14 +139,16 @@ without implementing them yourself. For example::
   template <> struct fmt::formatter<color>: formatter<string_view> {
     // parse is inherited from formatter<string_view>.
 
-    auto format(color c, format_context& ctx) const;
+    auto format(color c, format_context& ctx) const
+      -> format_parse_context::iterator;
   };
 
   // color.cc:
   #include "color.h"
   #include <fmt/format.h>
 
-  auto fmt::formatter<color>::format(color c, format_context& ctx) const {
+  auto fmt::formatter<color>::format(color c, format_context& ctx) const
+      -> format_parse_context::iterator {
     string_view name = "unknown";
     switch (c) {
     case color::red:   name = "red"; break;