c-api: turn const global into define (#150)

Issue: SILKIT-1654
vectorgrp · Nov 27, 2024 · 8eb649d · 8eb649d
1 parent d23f3a2
commit 8eb649d
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Showing 2 changed files with 11 additions and 1 deletion.
diff --git a/SilKit/include/silkit/capi/Lin.h b/SilKit/include/silkit/capi/Lin.h
@@ -161,7 +161,7 @@ typedef uint8_t SilKit_LinFrameStatus;
 typedef uint8_t SilKit_LinDataLength;
 
 //! \brief If configured for reception with this value, the data length validation of incoming frames is skipped.
-const SilKit_LinDataLength SilKit_LinDataLengthUnknown = 255u;
+#define SilKit_LinDataLengthUnknown ((SilKit_LinDataLength)255)
 
 /*! \brief A LIN SilKit_LinFrame
  *

diff --git a/docs/CHANGELOG.rst b/docs/CHANGELOG.rst
@@ -9,6 +9,16 @@ The format is based on `Keep a Changelog (http://keepachangelog.com/en/1.0.0/) <
 [4.0.55] - Unreleased
 ---------------------
 
+Fixed
+~~~~~
+
+- **Important** ``SilKit_LinDataLengthUnknown`` in the C header ``Lin.h`` used to be a ``const`` global, which could cause
+  linker issues if the header file is used in multiple translation units in the same binary.
+
+  It has been turned into a ``#define``, like all the other constants in the C header files.
+
+  The symbol was not present in the dynamic symbol table of the ``SilKit.dll`` / ``.so``, so this change
+  does not break the ABI of the shared libraries.
 
 
 [4.0.54] - 2024-11-11