diff --git a/libsrc/posixio.c b/libsrc/posixio.c
index 78f45d453b..2b404d2c76 100644
--- a/libsrc/posixio.c
+++ b/libsrc/posixio.c
@@ -536,7 +536,7 @@ px_get(ncio *const nciop, ncio_px *const pxp,
 	off_t diff = (size_t)(offset - blkoffset);
 	off_t blkextent = _RNDUP(diff + extent, pxp->blksz);
 
-	if(extent == 0 || extent >= X_INT_MAX || offset >= 0) /* sanity check */
+	if(!(extent != 0 && extent < X_INT_MAX && offset >= 0)) /* sanity check */
 	    return NC_ENOTNC;
 
 	if(2 * pxp->blksz < blkextent)