diff --git a/tests/data/Makefile.inc b/tests/data/Makefile.inc
index e6e9ae4570..a1a016554d 100644
--- a/tests/data/Makefile.inc
+++ b/tests/data/Makefile.inc
@@ -186,7 +186,7 @@ test1439 test1440 test1441 test1442 test1443 test1444 test1445 test1446 \
 test1447 test1448 test1449 test1450 test1451 test1452 test1453 test1454 \
 test1455 test1456 test1457 test1458 test1459 test1460 test1461 test1462 \
 test1463 test1464 test1465 test1466 test1467 test1468 test1469 test1470 \
-test1471 test1472 test1473 test1474 test1475 test1476 \
+test1471 test1472 test1473 test1474 test1475 test1476 test1477 \
 \
 test1500 test1501 test1502 test1503 test1504 test1505 test1506 test1507 \
 test1508 test1509 test1510 test1511 test1512 test1513 test1514 test1515 \
diff --git a/tests/data/test1477 b/tests/data/test1477
new file mode 100644
index 0000000000..2771d7f1d3
--- /dev/null
+++ b/tests/data/test1477
@@ -0,0 +1,30 @@
+<testcase>
+<info>
+<keywords>
+documentation
+</keywords>
+</info>
+
+#
+# Client-side
+<client>
+<server>
+none
+</server>
+
+<name>
+Verify that error codes in headers and libcurl-errors.3 are in sync
+</name>
+
+<command type="perl">
+%SRCDIR/errorcodes.pl %SRCDIR/..
+</command>
+</client>
+
+<verify>
+<stdout>
+Result
+</stdout>
+</verify>
+
+</testcase>
diff --git a/tests/errorcodes.pl b/tests/errorcodes.pl
new file mode 100755
index 0000000000..9c8f9e882d
--- /dev/null
+++ b/tests/errorcodes.pl
@@ -0,0 +1,99 @@
+#!/usr/bin/env perl
+#***************************************************************************
+#                                  _   _ ____  _
+#  Project                     ___| | | |  _ \| |
+#                             / __| | | | |_) | |
+#                            | (__| |_| |  _ <| |___
+#                             \___|\___/|_| \_\_____|
+#
+# Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
+#
+# This software is licensed as described in the file COPYING, which
+# you should have received as part of this distribution. The terms
+# are also available at https://curl.se/docs/copyright.html.
+#
+# You may opt to use, copy, modify, merge, publish, distribute and/or sell
+# copies of the Software, and permit persons to whom the Software is
+# furnished to do so, under the terms of the COPYING file.
+#
+# This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
+# KIND, either express or implied.
+#
+# SPDX-License-Identifier: curl
+#
+###########################################################################
+
+# Check that libcurl-errors.3 and the public header files have the same set of
+# error codes.
+
+use strict;
+use warnings;
+
+# we may get the dir roots pointed out
+my $root=$ARGV[0] || ".";
+my $manpge = "$root/docs/libcurl/libcurl-errors.3";
+my $curlh = "$root/include/curl";
+my $errors=0;
+
+my @hnames;
+my %wherefrom;
+my @mnames;
+my %manfrom;
+
+sub scanheader {
+    my ($file)=@_;
+    open H, "<$file";
+    my $line = 0;
+    while(<H>) {
+        $line++;
+        if($_ =~ /^  (CURL(E|UE|SHE|HE|M)_[A-Z0-9_]*)/) {
+            my ($name)=($1);
+            if(($name !~ /OBSOLETE/) && ($name !~ /_LAST\z/)) {
+                push @hnames, $name;
+                if($wherefrom{$name}) {
+                    print STDERR "double: $name\n";
+                }
+                $wherefrom{$name}="$file:$line";
+            }
+        }
+    }
+    close(H);
+}
+
+sub scanmanpage {
+    my ($file)=@_;
+    open H, "<$file";
+    my $line = 0;
+    while(<H>) {
+        $line++;
+        if($_ =~ /^\.IP \"(CURL(E|UE|SHE|HE|M)_[A-Z0-9_]*)/) {
+            my ($name)=($1);
+            push @mnames, $name;
+            $manfrom{$name}="$file:$line";
+        }
+    }
+    close(H);
+}
+
+
+opendir(my $dh, $curlh) || die "Can't opendir $curlh: $!";
+my @hfiles = grep { /\.h$/ } readdir($dh);
+closedir $dh;
+
+for(sort @hfiles) {
+    scanheader("$curlh/$_");
+}
+scanmanpage($manpge);
+
+print "Result\n";
+for my $h (sort @hnames) {
+    if(!$manfrom{$h}) {
+        printf "$h from %s, not in man page\n", $wherefrom{$h};
+    }
+}
+
+for my $m (sort @mnames) {
+    if(!$wherefrom{$m}) {
+        printf "$m from %s, not in any header\n", $manfrom{$m};
+    }
+}