Merge pull request #508 from jlmelville/develop

Provide a macro to override the use of std::cerr

Author: yurymalkov

hnswlib/hnswalg.h

@@ -105,8 +105,8 @@ class HierarchicalNSW : public AlgorithmInterface<dist_t> {
         if ( M <= 10000 ) {
             M_ = M;
         } else {
-            std::cerr << "warning: M parameter exceeds 10000 which may lead to adverse effects." << std::endl;
-            std::cerr << "         Cap to 10000 will be applied for the rest of the processing." << std::endl;
+            HNSWERR << "warning: M parameter exceeds 10000 which may lead to adverse effects." << std::endl;
+            HNSWERR << "         Cap to 10000 will be applied for the rest of the processing." << std::endl;
             M_ = 10000;
         }
         maxM_ = M_;

hnswlib/hnswlib.h

@@ -1,4 +1,13 @@
 #pragma once
+
+// https://github.com/nmslib/hnswlib/pull/508
+// This allows others to provide their own error stream (e.g. RcppHNSW)
+#ifndef HNSWLIB_ERR_OVERRIDE
+  #define HNSWERR std::cerr
+#else
+  #define HNSWERR HNSWLIB_ERR_OVERRIDE
+#endif
+
 #ifndef NO_MANUAL_VECTORIZATION
 #if (defined(__SSE__) || _M_IX86_FP > 0 || defined(_M_AMD64) || defined(_M_X64))
 #define USE_SSE