From 8f8d24280f34e5709b76b91462cc13b799dc51d1 Mon Sep 17 00:00:00 2001
From: Ahson Khan <ahson_ahmedk@yahoo.com>
Date: Mon, 7 Oct 2024 16:28:25 -0700
Subject: [PATCH] Fixed warning for an unused function in curl.cpp when
 building the SDK using a version of libcurl older than 7.77.0 (#6073)

---
 sdk/core/azure-core/CHANGELOG.md           | 2 ++
 sdk/core/azure-core/src/http/curl/curl.cpp | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/sdk/core/azure-core/CHANGELOG.md b/sdk/core/azure-core/CHANGELOG.md
index bec4be91e..577fa9d78 100644
--- a/sdk/core/azure-core/CHANGELOG.md
+++ b/sdk/core/azure-core/CHANGELOG.md
@@ -8,6 +8,8 @@
 
 ### Bugs Fixed
 
+- Fixed warning for an unused function in curl.cpp when building the SDK using a version of libcurl older than 7.77.0.
+
 ### Other Changes
 
 ## 1.14.0 (2024-10-03)
diff --git a/sdk/core/azure-core/src/http/curl/curl.cpp b/sdk/core/azure-core/src/http/curl/curl.cpp
index 176e61247..c11123174 100644
--- a/sdk/core/azure-core/src/http/curl/curl.cpp
+++ b/sdk/core/azure-core/src/http/curl/curl.cpp
@@ -275,6 +275,9 @@ static void CleanupThread()
   }
 }
 
+// This function is only used when ExpectedTlsRootCertificate transport options is set to non empty.
+// And that capability only impacts the curl transport behavior in versions of libcurl >= 7.77.0.
+#if LIBCURL_VERSION_NUM >= 0x074D00 // 7.77.0
 std::string PemEncodeFromBase64(std::string const& base64, std::string const& pemType)
 {
   std::stringstream rv;
@@ -293,6 +296,7 @@ std::string PemEncodeFromBase64(std::string const& base64, std::string const& pe
   rv << encodedValue << std::endl << "-----END " << pemType << "-----" << std::endl;
   return rv.str();
 }
+#endif
 
 Azure::Core::Http::CurlTransportOptions CurlTransportOptionsFromTransportOptions(
     Azure::Core::Http::Policies::TransportOptions const& transportOptions)