diff --git a/cpp/Cargo.lock b/cpp/Cargo.lock
index 2fd308e..11a963c 100644
--- a/cpp/Cargo.lock
+++ b/cpp/Cargo.lock
@@ -1,13 +1,5 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-[[package]]
-name = "aho-corasick"
-version = "0.6.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "memchr 2.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
 [[package]]
 name = "aho-corasick"
 version = "0.7.4"
@@ -23,55 +15,61 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "cc"
-version = "1.0.37"
+version = "1.0.50"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "cpp"
-version = "0.5.3"
+version = "0.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cpp_macros 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cpp_macros 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "cpp_build"
-version = "0.5.3"
+version = "0.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cc 1.0.37 (registry+https://github.com/rust-lang/crates.io-index)",
- "cpp_common 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cpp_common 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
- "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "cpp_common"
-version = "0.5.3"
+version = "0.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "cpp_macros"
-version = "0.5.3"
+version = "0.5.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "aho-corasick 0.6.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "aho-corasick 0.7.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "cpp_common 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cpp_common 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "if_rust_version 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 0.15.39 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 1.0.14 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "if_rust_version"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "lazy_static"
 version = "1.3.0"
@@ -84,18 +82,18 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "proc-macro2"
-version = "0.4.30"
+version = "1.0.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "quote"
-version = "0.6.13"
+version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -122,18 +120,18 @@ dependencies = [
 name = "rust_sample_cpp"
 version = "0.1.0"
 dependencies = [
- "cpp 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "cpp_build 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cpp 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cpp_build 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "syn"
-version = "0.15.39"
+version = "1.0.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro2 1.0.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -151,7 +149,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "unicode-xid"
-version = "0.1.0"
+version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -160,22 +158,22 @@ version = "1.0.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
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-"checksum cc 1.0.37 (registry+https://github.com/rust-lang/crates.io-index)" = "39f75544d7bbaf57560d2168f28fd649ff9c76153874db88bdbdfd839b1a7e7d"
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-"checksum cpp_build 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3b1282629429cdf0740399fd108fdc57d3e560c10c7f192a67d8ae3d1c0305cd"
-"checksum cpp_common 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "cd56d2b23d3b0843ae574e1b89fd15736a2775236e92415f353de24eee50480b"
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diff --git a/cpp/Cargo.toml b/cpp/Cargo.toml
index ffa9819..9b0592e 100644
--- a/cpp/Cargo.toml
+++ b/cpp/Cargo.toml
@@ -6,8 +6,8 @@ edition = "2018"
 build = "build.rs"
 
 [dependencies]
-cpp = "0.5.3"
+cpp = "0.5.4"
 
 [build-dependencies]
-cpp_build = "0.5.3"
+cpp_build = "0.5.4"