diff --git a/libc/docs/CHANGES.TXT b/libc/docs/CHANGES.TXT
index 2ae91d5b4..b57e87ac0 100644
--- a/libc/docs/CHANGES.TXT
+++ b/libc/docs/CHANGES.TXT
@@ -18,6 +18,9 @@ Differences between current and Android 2.2:
 
 - <termio.h>: added missing header (just includes <termios.h>)
 
+- <unistd.h>: add missing declaration for truncate(). The implementation
+  was already here since Android 1.5.
+
 -------------------------------------------------------------------------------
 Differences between Android 2.2. and Android 2.1:
 
diff --git a/libc/include/unistd.h b/libc/include/unistd.h
index b4f1dda17..75541980d 100644
--- a/libc/include/unistd.h
+++ b/libc/include/unistd.h
@@ -124,6 +124,7 @@ extern int readlink(const char *, char *, size_t);
 extern int chown(const char *, uid_t, gid_t);
 extern int fchown(int, uid_t, gid_t);
 extern int lchown(const char *, uid_t, gid_t);
+extern int truncate(const char *, off_t);
 extern char *getcwd(char *, size_t);
 
 extern int sync(void);