diff --git a/CMakeLists.txt b/CMakeLists.txt
index 807fc2f..623b09c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,6 +7,7 @@
 cmake_minimum_required(VERSION 3.2)
 project(maconv)
 
+set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wextra")
 
 # Compile vendor libraries.
 add_subdirectory("vendors/libhfs")
diff --git a/src/conv/binhex.cc b/src/conv/binhex.cc
index c9f7c56..c46a647 100644
--- a/src/conv/binhex.cc
+++ b/src/conv/binhex.cc
@@ -27,7 +27,7 @@ namespace conv {
 
 
 // Return true if a file is in BinHex format.
-bool IsFileBinHex(fs::FileReader &reader)
+bool IsFileBinHex(fs::FileReader &/* reader */)
 {
     // TODO.
 
@@ -37,7 +37,7 @@ bool IsFileBinHex(fs::FileReader &reader)
 
 
 // Read and decode a BinHex file.
-void ReadBinHex(fs::FileReader &reader, fs::File &file)
+void ReadBinHex(fs::FileReader &/* reader */, fs::File &/* file */)
 {
     // TODO.
 }
@@ -45,7 +45,7 @@ void ReadBinHex(fs::FileReader &reader, fs::File &file)
 
 
 // Write a BinHex file.
-void WriteBinHex(fs::File &file, fs::FileWriter &writer)
+void WriteBinHex(fs::File &/* file */, fs::FileWriter &/* writer */)
 {
     // TODO.
 }
diff --git a/src/disk/extract.cc b/src/disk/extract.cc
index 1bf0e27..6372cd7 100644
--- a/src/disk/extract.cc
+++ b/src/disk/extract.cc
@@ -38,7 +38,7 @@ static void ExtractFork(hfsfile *hfile, const hfsdirent &ent, fs::File &file,
     bool is_res)
 {
     // Allocate buffer.
-    int size = is_res ? ent.u.file.rsize : ent.u.file.dsize;
+    long unsigned int size = is_res ? ent.u.file.rsize : ent.u.file.dsize;
     auto buffer = std::make_unique<uint8_t[]>(size);
 
     // Read the data.
diff --git a/src/formats/file_signature.cc b/src/formats/file_signature.cc
index a888864..28bd5ce 100644
--- a/src/formats/file_signature.cc
+++ b/src/formats/file_signature.cc
@@ -59,10 +59,11 @@ SignToMac signs_to_mac[] = {
 
 
 // File signature array.
+/*
 SignToUnix signs_to_unix[] = {
 
 };
-
+*/
 
 
 // Call Unix "file" command on a path.
diff --git a/src/formats/file_signature.h b/src/formats/file_signature.h
index 60b3d6f..dc024c2 100644
--- a/src/formats/file_signature.h
+++ b/src/formats/file_signature.h
@@ -33,14 +33,14 @@ struct SignToMac {
     // Maching type: extension or file command.
     enum Type { Extension, FileCmd } type;
 
-    // Help strings (and count)
-    int help_len;
-    const char **helps;
-
     // MAC creator and type.
     const char *creator;
     const char *mac;
 
+    // Help strings (and count)
+    int help_len;
+    const char **helps;
+
     constexpr SignToMac(Type t, const char *c, const char *m, const char **hs, int hl)
         : type{t}, creator{c}, mac{m}, help_len{hl}, helps{hs} {}
 };
@@ -57,8 +57,9 @@ struct SignToUnix {
 extern SignToMac signs_to_mac[];
 
 // File signature array.
+/*
 extern SignToUnix signs_to_unix[];
-
+*/
 
 
 // Get the MAC type (and creator) for a specific file.
diff --git a/src/formats/formats.cc b/src/formats/formats.cc
index c17c04b..6eb6197 100644
--- a/src/formats/formats.cc
+++ b/src/formats/formats.cc
@@ -34,7 +34,7 @@ namespace maconv {
 
 
 // Prefered conversion format.
-ConvData prefered_conv = { ConvData::NotFound };
+ConvData prefered_conv = { ConvData::NotFound, NULL };
 
 
 // All available converters.
@@ -69,7 +69,7 @@ ConvData GetConverter(const std::string &name)
             return ConvData { ConvData::Double, &format };
     }
 
-    return ConvData { ConvData::NotFound };
+    return ConvData { ConvData::NotFound, NULL };
 }
 
 
diff --git a/src/fs/file.cc b/src/fs/file.cc
index cb714bd..4c296bc 100644
--- a/src/fs/file.cc
+++ b/src/fs/file.cc
@@ -71,13 +71,12 @@ int ReadLocalFile(const std::string &filename, fs::DataPtr &ptr)
 
 
 // Get file infotmation from a local file.
-void GetLocalInfo(const std::string &filename, fs::File &file, bool is_res)
+void GetLocalInfo(const std::string & /*filename */, fs::File &/* file */, bool /* is_res */)
 {
     // TODO.
 }
 
 
-
 // Set file infotmation to a local file.
 void SetLocalInfo(fs::File &file, const std::string &filename, bool is_res)
 {
diff --git a/src/fs/file_reader.h b/src/fs/file_reader.h
index c469509..df3c7bb 100644
--- a/src/fs/file_reader.h
+++ b/src/fs/file_reader.h
@@ -71,10 +71,10 @@ struct FileReader {
 
     uint8_t *data; // Input data.
     uint32_t file_size; // Total size of the file.
+    std::string filename; // Name of the file to read.
 
     utils::RawDataStreamBuf stream_buf; // Stream buffer from raw data buffer.
     std::istream stream; // Stream for reading data.
-    std::string filename; // Name of the file to read.
 };
 
 
diff --git a/src/stuffit/methods.cc b/src/stuffit/methods.cc
index 452f121..5517000 100644
--- a/src/stuffit/methods.cc
+++ b/src/stuffit/methods.cc
@@ -68,7 +68,7 @@ void CompressionMethod::Extract(const StuffitCompInfo &info, uint8_t *data,
     total_size = 0;
 
     // Uncompress the data chunk by chunks.
-    for (uint32_t len = 0; true;) {
+    for (int32_t len = 0; true;) {
         len = ReadBytes(buffer.get() + total_size, capacity - total_size);
         if (len == -1)
             break;
@@ -89,7 +89,7 @@ void CompressionMethod::Extract(const StuffitCompInfo &info, uint8_t *data,
 
 // Extract data from the compressed fork.
 void NoneMethod::Extract(const StuffitCompInfo &info, uint8_t *data,
-    std::vector<fs::DataPtr> &mem_pool)
+    std::vector<fs::DataPtr> &/* mem_pool */)
 {
     total_size = info.size ? info.size : info.comp_size;
     uncompressed = data + info.offset;
diff --git a/src/stuffit/methods.h b/src/stuffit/methods.h
index 155fb37..2562f27 100644
--- a/src/stuffit/methods.h
+++ b/src/stuffit/methods.h
@@ -47,7 +47,7 @@ struct CompressionMethod {
 
 
     // Read the next bytes.
-    virtual int32_t ReadBytes(uint8_t *data, uint32_t length) { return -1; }
+    virtual int32_t ReadBytes(uint8_t * /* data */, uint32_t /* length */) { return -1; }
 
     // Initialize the algorithm.
     virtual void Initialize() {}
diff --git a/vendors/libhfs/btree.c b/vendors/libhfs/btree.c
index d7d1916..eb4da22 100644
--- a/vendors/libhfs/btree.c
+++ b/vendors/libhfs/btree.c
@@ -409,7 +409,7 @@ fail:
  * DESCRIPTION:	recursively locate a node and insert a record
  */
 static
-int insertx(node *np, byte *record, int *reclen)
+int insertx(node *np, byte *record, unsigned int *reclen)
 {
   node child;
   byte *rec;
diff --git a/vendors/libhfs/volume.c b/vendors/libhfs/volume.c
index 13ee121..ca80810 100644
--- a/vendors/libhfs/volume.c
+++ b/vendors/libhfs/volume.c
@@ -758,7 +758,7 @@ fail:
  * DESCRIPTION:	translate a pathname; return catalog information
  */
 int v_resolve(hfsvol **vol, const char *path,
-              CatDataRec *data, long *parid, char *fname, node *np)
+              CatDataRec *data, unsigned long *parid, char *fname, node *np)
 {
   unsigned long dirid;
   char name[HFS_MAX_FLEN + 1], *nptr;
diff --git a/vendors/libhfs/volume.h b/vendors/libhfs/volume.h
index ae8a093..6fde218 100644
--- a/vendors/libhfs/volume.h
+++ b/vendors/libhfs/volume.h
@@ -54,7 +54,7 @@ int v_putextrec(const ExtDataRec *, node *);
 int v_allocblocks(hfsvol *, ExtDescriptor *);
 int v_freeblocks(hfsvol *, const ExtDescriptor *);
 
-int v_resolve(hfsvol **, const char *, CatDataRec *, long *, char *, node *);
+int v_resolve(hfsvol **, const char *, CatDataRec *, unsigned long *, char *, node *);
 
 int v_adjvalence(hfsvol *, unsigned long, int, int);
 int v_mkdir(hfsvol *, unsigned long, const char *);