Removed `ZSTD_*_usingPrepared?Ctx()` declaration from public space
diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c
index e57f38d..9a94cd9 100644
--- a/lib/compress/zstd_compress.c
+++ b/lib/compress/zstd_compress.c
@@ -2449,7 +2449,12 @@
 }
 
 
-size_t ZSTD_compress_usingPreparedCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx,
+/*! ZSTD_compress_usingPreparedCCtx() :
+*   Same as ZSTD_compress_usingDict, but using a reference context `preparedCCtx`, where dictionary has been loaded.
+*   It avoids reloading the dictionary each time.
+*   `preparedCCtx` must have been properly initialized using ZSTD_compressBegin_usingDict() or ZSTD_compressBegin_advanced().
+*   Requires 2 contexts : 1 for reference (preparedCCtx) which will not be modified, and 1 to run the compression operation (cctx) */
+static size_t ZSTD_compress_usingPreparedCCtx(ZSTD_CCtx* cctx, const ZSTD_CCtx* preparedCCtx,
                                        void* dst, size_t dstCapacity,
                                  const void* src, size_t srcSize)
 {