From a23d193100612be56e3d7a729ebe87feca15e98b Mon Sep 17 00:00:00 2001
From: Richard Hulme <r_hulme@yahoo.com>
Date: Wed, 29 Jan 2025 17:46:31 +0100
Subject: [PATCH] Declare platform.h functions with C linkage

The platform.h headers for both RP2040 and RP2350 need 'extern "C"'
declarations when included from C++ code or 'rp2040_chip_version'
and 'rp2350_chip_version' won't be found by the linker.
---
 src/rp2040/pico_platform/include/pico/platform.h | 8 ++++++++
 src/rp2350/pico_platform/include/pico/platform.h | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/src/rp2040/pico_platform/include/pico/platform.h b/src/rp2040/pico_platform/include/pico/platform.h
index 47aa119a7..5c157f532 100644
--- a/src/rp2040/pico_platform/include/pico/platform.h
+++ b/src/rp2040/pico_platform/include/pico/platform.h
@@ -77,6 +77,10 @@
 
 #ifndef __ASSEMBLER__
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /*! \brief No-op function for the body of tight loops
  *  \ingroup pico_platform
  *
@@ -210,6 +214,10 @@ return a;
     (__builtin_popcount(b) >= 2 ? __mul_instruction(a,b) : (a)*(b)), \
     (a)*(b))
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif // __ASSEMBLER__
 
 #endif
diff --git a/src/rp2350/pico_platform/include/pico/platform.h b/src/rp2350/pico_platform/include/pico/platform.h
index 24fec75bb..35a6a0bd6 100644
--- a/src/rp2350/pico_platform/include/pico/platform.h
+++ b/src/rp2350/pico_platform/include/pico/platform.h
@@ -70,6 +70,10 @@
 
 #ifndef __ASSEMBLER__
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /*! \brief No-op function for the body of tight loops
  *  \ingroup pico_platform
  *
@@ -281,6 +285,10 @@ __force_inline static int32_t __mul_instruction(int32_t a, int32_t b) {
     (__builtin_popcount(b) >= 2 ? __mul_instruction(a,b) : (a)*(b)), \
     (a)*(b))
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif // __ASSEMBLER__
 
 #endif