diff --git a/src/lcpex/helpers.h b/src/lcpex/helpers.h
index 7c458b7..802a8da 100644
--- a/src/lcpex/helpers.h
+++ b/src/lcpex/helpers.h
@@ -16,6 +16,18 @@ enum CHILD_PIPE_NAMES {
 
 #define BUFFER_SIZE 1024
 
-ssize_t write_all(int fd, const void *buf, size_t count);
+ssize_t write_all(int fd, const void *buf, size_t count) {
+    const char *p = (const char *)buf;
+    while (count > 0) {
+        ssize_t written = write(fd, p, count);
+        if (written == -1) {
+            if (errno == EINTR || errno == EAGAIN) continue; // Retry
+            return -1; // Other errors
+        }
+        count -= written;
+        p += written;
+    }
+    return 0;
+}
 
 #endif //LCPEX_HELPERS_H