diff --git a/libc/spec/posix.td b/libc/spec/posix.td
--- a/libc/spec/posix.td
+++ b/libc/spec/posix.td
@@ -425,7 +425,7 @@
         FunctionSpec<
           "ftruncate",
           RetValSpec<IntType>,
-          [ArgSpec<ConstCharPtr>, ArgSpec<OffTType>]
+          [ArgSpec<IntType>, ArgSpec<OffTType>]
         >,
         FunctionSpec<
           "geteuid",
@@ -580,7 +580,7 @@
         FunctionSpec<
           "truncate",
           RetValSpec<IntType>,
-          [ArgSpec<IntType>, ArgSpec<OffTType>]
+          [ArgSpec<ConstCharPtr>, ArgSpec<OffTType>]
         >,
         FunctionSpec<
           "unlink",