diff --git a/lib/libz/compress.3 b/lib/libz/compress.3
index 104f0b8d9ca..114d9b2b329 100644
--- a/lib/libz/compress.3
+++ b/lib/libz/compress.3
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: compress.3,v 1.34 2026/03/19 15:11:47 tb Exp $
+.\"	$OpenBSD: compress.3,v 1.35 2026/03/23 09:11:44 jsg Exp $
 .\"
 .\"  Copyright (C) 1995-2017 Jean-loup Gailly and Mark Adler
 .\"
@@ -21,7 +21,7 @@
 .\" Converted to mdoc format for the OpenBSD project
 .\" by Jason McIntyre <jmc@openbsd.org>
 .\"
-.Dd $Mdocdate: March 19 2026 $
+.Dd $Mdocdate: March 23 2026 $
 .Dt COMPRESS 3
 .Os
 .Sh NAME
@@ -2854,7 +2854,7 @@ return
 and errno will be
 .Dv EAGAIN
 or
-.Dv ENONBLOCK .
+.Dv EWOULDBLOCK .
 The call to
 .Fn gzopen
 with the resulting file descriptor and
diff --git a/lib/libz/zlib.h b/lib/libz/zlib.h
index a57d3361342..1b306017972 100644
--- a/lib/libz/zlib.h
+++ b/lib/libz/zlib.h
@@ -1394,7 +1394,7 @@ ZEXTERN gzFile ZEXPORT gzopen(const char *path, const char *mode);
    errno can be checked to determine if the reason gzopen failed was that the
    file could not be opened. Note that if 'N' is in mode for non-blocking, the
    open() itself can fail in order to not block. In that case gzopen() will
-   return NULL and errno will be EAGAIN or ENONBLOCK. The call to gzopen() can
+   return NULL and errno will be EAGAIN or EWOULDBLOCK. The call to gzopen() can
    then be re-tried. If the application would like to block on opening the
    file, then it can use open() without O_NONBLOCK, and then gzdopen() with the
    resulting file descriptor and 'N' in the mode, which will set it to non-
diff --git a/sys/lib/libz/zlib.h b/sys/lib/libz/zlib.h
index 23a9658d0c2..ca31baea101 100644
--- a/sys/lib/libz/zlib.h
+++ b/sys/lib/libz/zlib.h
@@ -1394,7 +1394,7 @@ ZEXTERN gzFile ZEXPORT gzopen(const char *path, const char *mode);
    errno can be checked to determine if the reason gzopen failed was that the
    file could not be opened. Note that if 'N' is in mode for non-blocking, the
    open() itself can fail in order to not block. In that case gzopen() will
-   return NULL and errno will be EAGAIN or ENONBLOCK. The call to gzopen() can
+   return NULL and errno will be EAGAIN or EWOULDBLOCK. The call to gzopen() can
    then be re-tried. If the application would like to block on opening the
    file, then it can use open() without O_NONBLOCK, and then gzdopen() with the
    resulting file descriptor and 'N' in the mode, which will set it to non-