3 files changed, 12 insertions, 4 deletions
diff --git a/alacritty_terminal/src/ansi.rs b/alacritty_terminal/src/ansi.rs
index 06ea0234..91dd3540 100644
--- a/alacritty_terminal/src/ansi.rs
+++ b/alacritty_terminal/src/ansi.rs
@@ -770,6 +770,8 @@ pub enum Attr {
     Underline,
     /// Underlined twice.
     DoubleUnderline,
+    /// Undercurled text.
+    Undercurl,
     /// Blink cursor slowly.
     BlinkSlow,
     /// Blink cursor fast.
@@ -1329,6 +1331,7 @@ fn attrs_from_sgr_parameters(params: &mut ParamsIter<'_>) -> Vec<Option<Attr>> {
             [3] => Some(Attr::Italic),
             [4, 0] => Some(Attr::CancelUnderline),
             [4, 2] => Some(Attr::DoubleUnderline),
+            [4, 3] => Some(Attr::Undercurl),
             [4, ..] => Some(Attr::Underline),
             [5] => Some(Attr::BlinkSlow),
             [6] => Some(Attr::BlinkFast),
diff --git a/alacritty_terminal/src/term/cell.rs b/alacritty_terminal/src/term/cell.rs
index 64de5492..49d25eb3 100644
--- a/alacritty_terminal/src/term/cell.rs
+++ b/alacritty_terminal/src/term/cell.rs
@@ -24,6 +24,8 @@ bitflags! {
         const STRIKEOUT                 = 0b0000_0010_0000_0000;
         const LEADING_WIDE_CHAR_SPACER  = 0b0000_0100_0000_0000;
         const DOUBLE_UNDERLINE          = 0b0000_1000_0000_0000;
+        const UNDERCURL                 = 0b0001_0000_0000_0000;
+        const ALL_UNDERLINES            = Self::UNDERLINE.bits | Self::DOUBLE_UNDERLINE.bits | Self::UNDERCURL.bits;
     }
 }
 
@@ -119,6 +121,7 @@ impl GridCell for Cell {
                 Flags::INVERSE
                     | Flags::UNDERLINE
                     | Flags::DOUBLE_UNDERLINE
+                    | Flags::UNDERCURL
                     | Flags::STRIKEOUT
                     | Flags::WRAPLINE
                     | Flags::WIDE_CHAR_SPACER
diff --git a/alacritty_terminal/src/term/mod.rs b/alacritty_terminal/src/term/mod.rs
index 50f423e5..4d30602b 100644
--- a/alacritty_terminal/src/term/mod.rs
+++ b/alacritty_terminal/src/term/mod.rs
@@ -1839,16 +1839,18 @@ impl<T: EventListener> Handler for Term<T> {
             Attr::Italic => cursor.template.flags.insert(Flags::ITALIC),
             Attr::CancelItalic => cursor.template.flags.remove(Flags::ITALIC),
             Attr::Underline => {
-                cursor.template.flags.remove(Flags::DOUBLE_UNDERLINE);
+                cursor.template.flags.remove(Flags::ALL_UNDERLINES);
                 cursor.template.flags.insert(Flags::UNDERLINE);
             },
             Attr::DoubleUnderline => {
-                cursor.template.flags.remove(Flags::UNDERLINE);
+                cursor.template.flags.remove(Flags::ALL_UNDERLINES);
                 cursor.template.flags.insert(Flags::DOUBLE_UNDERLINE);
             },
-            Attr::CancelUnderline => {
-                cursor.template.flags.remove(Flags::UNDERLINE | Flags::DOUBLE_UNDERLINE);
+            Attr::Undercurl => {
+                cursor.template.flags.remove(Flags::ALL_UNDERLINES);
+                cursor.template.flags.insert(Flags::UNDERCURL);
             },
+            Attr::CancelUnderline => cursor.template.flags.remove(Flags::ALL_UNDERLINES),
             Attr::Hidden => cursor.template.flags.insert(Flags::HIDDEN),
             Attr::CancelHidden => cursor.template.flags.remove(Flags::HIDDEN),
             Attr::Strike => cursor.template.flags.insert(Flags::STRIKEOUT),