diff --git a/libi3/safewrappers.c b/libi3/safewrappers.c
index 04bbda44..1802b327 100644
--- a/libi3/safewrappers.c
+++ b/libi3/safewrappers.c
@@ -70,7 +70,7 @@ ssize_t writeall(int fd, const void *buf, size_t count) {
     size_t written = 0;
 
     while (written < count) {
-        const ssize_t n = write(fd, buf + written, count - written);
+        const ssize_t n = write(fd, ((char *)buf) + written, count - written);
         if (n == -1) {
             if (errno == EINTR || errno == EAGAIN)
                 continue;
@@ -86,7 +86,7 @@ ssize_t writeall_nonblock(int fd, const void *buf, size_t count) {
     size_t written = 0;
 
     while (written < count) {
-        const ssize_t n = write(fd, buf + written, count - written);
+        const ssize_t n = write(fd, ((char *)buf) + written, count - written);
         if (n == -1) {
             if (errno == EAGAIN) {
                 return written;