Fix EINTR handling for close

style.md

@@ -331,7 +331,7 @@ static_assert(std::is_trivially_destructible_v<T>, "Arena requires trivially des
 
 ### System Call Error Handling
 
-When a system call is interrupted by a signal (`EINTR`), it is usually necessary to retry the call. This is especially true for "slow" system calls that can block for a long time, such as `read`, `write`, `accept`, `connect`, `close`, `sem_wait`, and `epoll_wait`.
+When a system call is interrupted by a signal (`EINTR`), it is usually necessary to retry the call. This is especially true for "slow" system calls that can block for a long time, such as `read`, `write`, `accept`, `connect`, `sem_wait`, and `epoll_wait`.
 
 **Rule:** Always wrap potentially interruptible system calls in a `do-while` loop that checks for `EINTR`.
 
@@ -350,6 +350,20 @@ if (fd == -1) {
 }
 ```
 
+**Special case - close():**
+
+The `close()` system call is a special case on Linux. According to `man 2 close`, when `close()` returns `EINTR` on Linux, the file descriptor is still guaranteed to be closed. Therefore, `close()` should **never** be retried.
+
+```cpp
+// Correct: Do not retry close() on EINTR
+int e = close(fd);
+if (e == -1 && errno != EINTR) {
+  // Handle non-EINTR errors only
+  perror("close");
+  std::abort();
+}
+// Note: fd is guaranteed closed even on EINTR
+```
 
 **Non-interruptible calls:**
 
@@ -361,6 +375,7 @@ Most system calls are not interruptible in practice. For these, it is not necess
 *   `pipe`
 *   `setsockopt`
 *   `epoll_create1`
+*   `close` (special case: guaranteed closed even on EINTR on Linux)
 
 When in doubt, consult the `man` page for the specific system call to see if it can return `EINTR`.