diff --git a/libdap4/d4data.c b/libdap4/d4data.c
index 127d177b8..309ffa6a7 100644
--- a/libdap4/d4data.c
+++ b/libdap4/d4data.c
@@ -36,7 +36,7 @@ static unsigned NCD4_computeChecksum(NCD4meta* meta, NCD4node* topvar);
 /* Macro define procedures */
 
 #ifdef D4DUMPCSUM
-static unsigned int debugcrc32(unsigned int crc, const void *buf, size_t size)
+static unsigned int debugcrc32(unsigned int crc, const void *buf, unsigned int size)
 {
     int i;
     fprintf(stderr,"crc32: ");
@@ -443,7 +443,7 @@ NCD4_computeChecksum(NCD4meta* meta, NCD4node* topvar)
     ASSERT((ISTOPLEVEL(topvar)));
 
 #ifndef HYRAXCHECKSUM
-    csum = CRC32(csum,topvar->data.dap4data.memory,topvar->data.dap4data.size);
+    csum = CRC32(csum,topvar->data.dap4data.memory, (unsigned int)topvar->data.dap4data.size);
 #else
     if(topvar->basetype->subsort != NC_STRING) {
             csum = CRC32(csum,topvar->data.dap4data.memory,topvar->data.dap4data.size);