diff --git a/CHANGELOG.markdown b/CHANGELOG.markdown
index 5eedb94..1a316d5 100644
--- a/CHANGELOG.markdown
+++ b/CHANGELOG.markdown
@@ -14,6 +14,7 @@
   `sys::igIsWindowHovered(ImGuiHoveredFlags::RootAndChildWindows)`.
   - Obsolete `sys::SetNextWindowContentWidth()` in favor of using
   `sys::igSetNextWindowContentSize()`.
+  - Rename `sys::ImGuiTextBuffer_append()` helper to `appendf()`.
 
 
 ## [0.0.18] - 2017-12-23
diff --git a/imgui-sys/src/lib.rs b/imgui-sys/src/lib.rs
index 0997d2f..23db9bd 100644
--- a/imgui-sys/src/lib.rs
+++ b/imgui-sys/src/lib.rs
@@ -1790,7 +1790,7 @@ extern "C" {
     pub fn ImGuiTextBuffer_empty(buffer: *mut ImGuiTextBuffer) -> bool;
     pub fn ImGuiTextBuffer_clear(buffer: *mut ImGuiTextBuffer);
     pub fn ImGuiTextBuffer_c_str(buffer: *const ImGuiTextBuffer) -> *const c_char;
-    pub fn ImGuiTextBuffer_append(buffer: *const ImGuiTextBuffer, fmt: *const c_char, ...);
+    pub fn ImGuiTextBuffer_appendf(buffer: *const ImGuiTextBuffer, fmt: *const c_char, ...);
 // pub fn ImGuiTextBuffer_appendv(
 //     buffer: *const ImGuiTextBuffer,
 //     fmt: *const c_char,