fixed nonsense with truncation

src/lcpex/helpers.cpp

@@ -0,0 +1,15 @@
+#include "helpers.h"
+
+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;
+}