diff --git a/lib/file.c b/lib/file.c
index 91176aa11..8e4ee075f 100644
--- a/lib/file.c
+++ b/lib/file.c
@@ -146,7 +146,7 @@ static CURLcode file_range(struct connectdata *conn)
 
   if(data->state.use_range && data->state.range) {
     from=curlx_strtoofft(data->state.range, &ptr, 0);
-    while(*ptr && (isspace((int)*ptr) || (*ptr=='-')))
+    while(*ptr && (ISSPACE(*ptr) || (*ptr=='-')))
       ptr++;
     to=curlx_strtoofft(ptr, &ptr2, 0);
     if(ptr == ptr2) {
diff --git a/lib/openldap.c b/lib/openldap.c
index 6b059d10a..e9dcfcc71 100644
--- a/lib/openldap.c
+++ b/lib/openldap.c
@@ -511,14 +511,14 @@ static ssize_t ldap_recv(struct connectdata *conn, int sockindex, char *buf,
 
         if (!binary) {
           /* check for leading or trailing whitespace */
-          if (isspace(bvals[i].bv_val[0]) ||
-              isspace(bvals[i].bv_val[bvals[i].bv_len-1])) {
+          if (ISSPACE(bvals[i].bv_val[0]) ||
+              ISSPACE(bvals[i].bv_val[bvals[i].bv_len-1])) {
             binval = 1;
           } else {
             /* check for unprintable characters */
             unsigned int j;
             for (j=0; j<bvals[i].bv_len; j++)
-              if (!isprint(bvals[i].bv_val[j])) {
+              if (!ISPRINT(bvals[i].bv_val[j])) {
                 binval = 1;
                 break;
               }
diff --git a/lib/ssh.c b/lib/ssh.c
index 862ce76f6..52cf5ad98 100644
--- a/lib/ssh.c
+++ b/lib/ssh.c
@@ -1935,7 +1935,7 @@ static CURLcode ssh_statemach_act(struct connectdata *conn, bool *block)
           char *ptr2;
 
           from=curlx_strtoofft(conn->data->state.range, &ptr, 0);
-          while(*ptr && (isspace((int)*ptr) || (*ptr=='-')))
+          while(*ptr && (ISSPACE(*ptr) || (*ptr=='-')))
             ptr++;
           to=curlx_strtoofft(ptr, &ptr2, 0);
           if((ptr == ptr2) /* no "to" value given */