From 42160327dc55fd4a00634cc3fd461a5844aa8e73 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?R=C3=A9my=20Mathieu?= <remeh@remeh.fr>
Date: Sat, 15 Mar 2025 12:04:42 +0100
Subject: [PATCH] posix/write: catch MSGSIZE error (#23238)

---
 lib/std/posix.zig | 5 +++++
 src/fmt.zig       | 1 +
 2 files changed, 6 insertions(+)

diff --git a/lib/std/posix.zig b/lib/std/posix.zig
index c07d6e6f0d..f920784ca5 100644
--- a/lib/std/posix.zig
+++ b/lib/std/posix.zig
@@ -1198,6 +1198,10 @@ pub const WriteError = error{
     /// This error occurs when a device gets disconnected before or mid-flush
     /// while it's being written to - errno(6): No such device or address.
     NoDevice,
+
+    /// The socket type requires that message be sent atomically, and the size of the message
+    /// to be sent made this impossible. The message is not transmitted.
+    MessageTooBig,
 } || UnexpectedError;
 
 /// Write to a file descriptor.
@@ -1279,6 +1283,7 @@ pub fn write(fd: fd_t, bytes: []const u8) WriteError!usize {
             .CONNRESET => return error.ConnectionResetByPeer,
             .BUSY => return error.DeviceBusy,
             .NXIO => return error.NoDevice,
+            .MSGSIZE => return error.MessageTooBig,
             else => |err| return unexpectedErrno(err),
         }
     }
diff --git a/src/fmt.zig b/src/fmt.zig
index a86a4191d1..6b1d73951e 100644
--- a/src/fmt.zig
+++ b/src/fmt.zig
@@ -202,6 +202,7 @@ const FmtError = error{
     DestinationAddressRequired,
     DiskQuota,
     FileTooBig,
+    MessageTooBig,
     InputOutput,
     NoSpaceLeft,
     AccessDenied,