diff --git a/libdispatch/dfile.c b/libdispatch/dfile.c
index f696e9bf3..d198d1f00 100644
--- a/libdispatch/dfile.c
+++ b/libdispatch/dfile.c
@@ -125,7 +125,7 @@ NC_check_file_type(const char *path, int use_parallel, void *mpi_info,
       i = fread(magic, MAGIC_NUMBER_LEN, 1, fp);
       fclose(fp);
       if(i != 1)
-	 return errno;
+	 return NC_ENOTNC;
    }
     
    /* Ignore the first byte for HDF */
@@ -140,7 +140,10 @@ NC_check_file_type(const char *path, int use_parallel, void *mpi_info,
 	 *cdf = 1; /* netcdf classic version 1 */
       else if(magic[3] == '\002') 
 	 *cdf = 2; /* netcdf classic version 2 */
-   }
+      else
+	 return NC_ENOTNC;
+   } else
+	 return NC_ENOTNC;
     
    return NC_NOERR;
 }
@@ -1567,8 +1570,8 @@ NC_open(const char *path, int cmode,
 	 } else if(cdfversion != 0) {
 	    model = NC_DISPATCH_NC3;
 	 }
-      } 
-      /* else ignore the file */
+      } else /* presumably not a netcdf file */
+	return NC_ENOTNC;
    }
 
    /* Look to the incoming cmode for hints */
diff --git a/oc2/dapparselex.h b/oc2/dapparselex.h
index 34aaf9f57..852a72122 100644
--- a/oc2/dapparselex.h
+++ b/oc2/dapparselex.h
@@ -7,7 +7,6 @@
 #include "ocinternal.h"
 #include "ocdebug.h"
 
-
 /* For consistency with Java parser */
 #define null NULL
 
diff --git a/oc2/ocinternal.c b/oc2/ocinternal.c
index 532ab6e65..6410741c8 100644
--- a/oc2/ocinternal.c
+++ b/oc2/ocinternal.c
@@ -343,23 +343,24 @@ createtempfile1(char* tmppath, char** tmpnamep)
 {
     int fd = 0;
     char* tmpname = NULL;
-    tmpname = (char*)malloc(strlen(tmppath)+strlen("dataddsXXXXXX")+1);
+    int tmpsize = strlen(tmppath)+strlen("dataddsXXXXXX");
+    tmpname = (char*)malloc(tmpsize+1);
     if(tmpname == NULL) return -1;
-    strcpy(tmpname,tmppath);
+    strncpy(tmpname,tmppath,tmpsize);
 #ifdef HAVE_MKSTEMP
-    strcat(tmpname,"dataddsXXXXXX");
+    strncat(tmpname,"dataddsXXXXXX",strlen("dataddsXXXXXX")));
     /* Note Potential problem: old versions of this function
        leave the file in mode 0666 instead of 0600 */
     fd = mkstemp(tmpname);
 #else /* !HAVE_MKSTEMP */
     /* Need to simulate by using some kind of pseudo-random number */
-    strcat(tmpname,"datadds");
+    strncat(tmpname,"datadds",strlen("datadds"));
     {
 	int rno = rand();
 	char spid[7];
 	if(rno < 0) rno = -rno;
-        sprintf(spid,"%06d",rno);
-        strcat(tmpname,spid);
+        snprintf(spid,sizeof(spid),"%06d",rno);
+        strncat(tmpname,spid,strlen(spid));
 #  ifdef WIN32
         fd=open(tmpname,O_RDWR|O_BINARY|O_CREAT|O_EXCL|FILE_ATTRIBUTE_TEMPORARY, _S_IREAD|_S_IWRITE);
 #  else
@@ -371,7 +372,6 @@ createtempfile1(char* tmppath, char** tmpnamep)
     if(tmpnamep) *tmpnamep = tmpname;
     else
       free(tmpname);
-
     return fd;
 }
 
@@ -557,8 +557,8 @@ ocsetcurlproperties(OCstate* state)
 	}
     }
     if(state->curlflags.useragent == NULL) {
-        size_t len = strlen(DFALTUSERAGENT) + strlen(VERSION) + 1;
-	char* agent = (char*)malloc(len);
+        size_t len = strlen(DFALTUSERAGENT) + strlen(VERSION);
+	char* agent = (char*)malloc(len+1);
 	snprintf(agent,len,"%s%s",DFALTUSERAGENT,VERSION);
 	state->curlflags.useragent = agent;
     }
diff --git a/oc2/ocinternal.h b/oc2/ocinternal.h
index 991f83fcb..42ec1e6ab 100644
--- a/oc2/ocinternal.h
+++ b/oc2/ocinternal.h
@@ -13,10 +13,12 @@
 #include <stdlib.h>
 #include <assert.h>
 #include <string.h>
-#ifndef WIN32
+#ifdef HAVE_STRINGS_H
 #include <strings.h>
 #endif
+#ifdef HAVE_STDARG_H
 #include <stdarg.h>
+#endif
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif
diff --git a/oc2/ocutil.c b/oc2/ocutil.c
index a78b61c2c..12736f3a4 100644
--- a/oc2/ocutil.c
+++ b/oc2/ocutil.c
@@ -551,3 +551,47 @@ ocdtmodestring(OCDT mode,int compact)
     }
     return result;
 }
+
+
+/*
+Instead of using snprintf to concatenate
+multiple strings into a given target,
+provide a direct concatenator.
+So, this function concatenates n strings
+into dst, being careful to not overrun size.
+Note that size is assumed to include the null
+terminator and that in the event of overrun,
+the string will have a null at dst[size-1].
+Return -1 if overrun, 0 otherwise.
+*/
+int
+occoncat(char* dst, size_t size, size_t n, ...)
+{
+    va_list args;
+    size_t avail = size - 1;
+    int i; 
+    int status = 0; // assume ok
+    char* p = dst;
+
+    if(n == 0) {
+	if(size > 0)
+	    dst[0] = '\0';
+	return (size > 0 ? 0: -1);
+    }
+	
+    va_start(args,n);
+    for(i=0;i<n;i++) {
+	char* q = va_arg(args, char*);
+	for(;;) {
+	    int c = *q++;
+	    if(c == '\0') break;
+	    if(avail == 0) {status = -1; goto done;}
+	    *p++ = c;
+	    avail--;
+	}
+    }
+
+done:
+    va_end(args);
+    return status;    
+}
diff --git a/oc2/ocutil.h b/oc2/ocutil.h
index 58c3895aa..71d67aefb 100644
--- a/oc2/ocutil.h
+++ b/oc2/ocutil.h
@@ -43,6 +43,8 @@ extern void ocdataddsmsg(struct OCstate*, struct OCtree*);
 
 extern const char* ocdtmodestring(OCDT mode,int compact);
 
+extern int occoncat(char* dst, size_t size, size_t n, ...);
+
 /* Define some classifiers */
 #define iscontainer(t) ((t) == OC_Dataset || (t) == OC_Structure || (t) == OC_Sequence || (t) == OC_Grid)