diff --git a/common/sudo_debug.c b/common/sudo_debug.c
index 10251cf24..c46bf3634 100644
--- a/common/sudo_debug.c
+++ b/common/sudo_debug.c
@@ -146,7 +146,7 @@ int sudo_debug_init(const char *debugfile, const char *settings)
 	    }
 	    if (sudo_debug_fd == -1)
 		return 0;
-	    fchown(sudo_debug_fd, (uid_t)-1, 0);
+	    ignore_result(fchown(sudo_debug_fd, (uid_t)-1, 0));
 	}
 	(void)fcntl(sudo_debug_fd, F_SETFD, FD_CLOEXEC);
 	sudo_debug_mode = SUDO_DEBUG_MODE_FILE;
diff --git a/plugins/sudoers/iolog.c b/plugins/sudoers/iolog.c
index 7a99b4afb..ce5c86e4d 100644
--- a/plugins/sudoers/iolog.c
+++ b/plugins/sudoers/iolog.c
@@ -139,7 +139,7 @@ io_mkdirs(char *path, mode_t mode, bool is_temp)
 	if (stat(path, &sb) != 0) {
 	    if (mkdir(path, mode) != 0)
 		log_fatal(USE_ERRNO, N_("unable to mkdir %s"), path);
-	    (void) chown(path, (uid_t)-1, parent_gid);
+	    ignore_result(chown(path, (uid_t)-1, parent_gid));
 	} else if (!S_ISDIR(sb.st_mode)) {
 	    log_fatal(0, N_("%s exists but is not a directory (0%o)"),
 		path, (unsigned int) sb.st_mode);
@@ -153,11 +153,11 @@ io_mkdirs(char *path, mode_t mode, bool is_temp)
     if (is_temp) {
 	if (mkdtemp(path) == NULL)
 	    log_fatal(USE_ERRNO, N_("unable to mkdir %s"), path);
-	(void) chown(path, (uid_t)-1, parent_gid);
+	ignore_result(chown(path, (uid_t)-1, parent_gid));
     } else {
 	if (mkdir(path, mode) != 0 && errno != EEXIST)
 	    log_fatal(USE_ERRNO, N_("unable to mkdir %s"), path);
-	(void) chown(path, (uid_t)-1, parent_gid);
+	ignore_result(chown(path, (uid_t)-1, parent_gid));
     }
     debug_return;
 }
diff --git a/plugins/sudoers/set_perms.c b/plugins/sudoers/set_perms.c
index 278392a67..a887a5124 100644
--- a/plugins/sudoers/set_perms.c
+++ b/plugins/sudoers/set_perms.c
@@ -1085,7 +1085,7 @@ restore_perms(void)
     if (OID(euid) == ROOT_UID) {
 	/* setuid() may not set the saved ID unless the euid is ROOT_UID */
 	if (ID(euid) != ROOT_UID)
-	    (void)setreuid(-1, ROOT_UID);
+	    ignore_result(setreuid(-1, ROOT_UID));
 	if (setuid(ROOT_UID)) {
 	    warning("setuid() [%d, %d] -> %d)", (int)state->ruid,
 		(int)state->euid, ROOT_UID);
diff --git a/src/sudo.c b/src/sudo.c
index 5a849efd3..0de32d4c1 100644
--- a/src/sudo.c
+++ b/src/sudo.c
@@ -276,7 +276,8 @@ main(int argc, char *argv[], char *envp[])
 	    if (ISSET(sudo_mode, MODE_BACKGROUND))
 		SET(command_details.flags, CD_BACKGROUND);
 	    /* Become full root (not just setuid) so user cannot kill us. */
-	    (void) setuid(ROOT_UID);
+	    if (setuid(ROOT_UID) == -1)
+		warning("setuid(%d)", ROOT_UID);
 	    /* Restore coredumpsize resource limit before running. */
 #ifdef RLIMIT_CORE
 	    if (sudo_conf_disable_coredump())
diff --git a/src/tgetpass.c b/src/tgetpass.c
index d8d77e1fa..31194b963 100644
--- a/src/tgetpass.c
+++ b/src/tgetpass.c
@@ -225,7 +225,8 @@ sudo_askpass(const char *askpass, const char *prompt)
 	    warning("dup2");
 	    _exit(255);
 	}
-	(void) setuid(ROOT_UID);
+	if (setuid(ROOT_UID) == -1)
+	    warning("setuid(%d)", ROOT_UID);
 	if (setgid(user_details.gid)) {
 	    warning(_("unable to set gid to %u"), (unsigned int)user_details.gid);
 	    _exit(255);