diff --git a/src/close.c b/src/close.c
index 0140f60..71873cf 100644
--- a/src/close.c
+++ b/src/close.c
@@ -28,9 +28,9 @@
 
 int aaruf_close(void *context)
 {
-    int            i;
-    mediaTagEntry *mediaTag;
-    mediaTagEntry *tmpMediaTag;
+    int i = 0;
+    mediaTagEntry *mediaTag = NULL;
+    mediaTagEntry *tmpMediaTag = NULL;
 
     if(context == NULL)
     {
diff --git a/src/crc64/crc64.c b/src/crc64/crc64.c
index dc4508f..a570946 100644
--- a/src/crc64/crc64.c
+++ b/src/crc64/crc64.c
@@ -22,7 +22,6 @@
 
 AARU_EXPORT crc64_ctx *AARU_CALL aaruf_crc64_init(void)
 {
-    int        i, slice;
     crc64_ctx *ctx = (crc64_ctx *)malloc(sizeof(crc64_ctx));
 
     if(!ctx) return NULL;
@@ -68,7 +67,7 @@ AARU_EXPORT void AARU_CALL aaruf_crc64_slicing(uint64_t *previous_crc, const uin
 
     if(len > 4)
     {
-        const uint8_t *limit;
+        const uint8_t *limit = NULL;
 
         while((uintptr_t)(data) & 3)
         {
diff --git a/src/cst.c b/src/cst.c
index 559070a..28edadc 100644
--- a/src/cst.c
+++ b/src/cst.c
@@ -24,15 +24,22 @@
 
 int32_t aaruf_cst_transform(const uint8_t *interleaved, uint8_t *sequential, size_t length)
 {
-    uint8_t *p, *q, *r, *s, *t, *u, *v, *w;
-    size_t   qStart;
-    size_t   rStart;
-    size_t   sStart;
-    size_t   tStart;
-    size_t   uStart;
-    size_t   vStart;
-    size_t   wStart;
-    size_t   i;
+    uint8_t *p = NULL;
+    uint8_t *q = NULL;
+    uint8_t *r = NULL;
+    uint8_t *s = NULL;
+    uint8_t *t = NULL;
+    uint8_t *u = NULL;
+    uint8_t *v = NULL;
+    uint8_t *w = NULL;
+    size_t qStart = 0;
+    size_t rStart = 0;
+    size_t sStart = 0;
+    size_t tStart = 0;
+    size_t uStart = 0;
+    size_t vStart = 0;
+    size_t wStart = 0;
+    size_t i = 0;
 
     if(interleaved == NULL || sequential == NULL) return AARUF_ERROR_BUFFER_TOO_SMALL;
 
diff --git a/src/ecc_cd.c b/src/ecc_cd.c
index 10d8657..a960ae9 100644
--- a/src/ecc_cd.c
+++ b/src/ecc_cd.c
@@ -26,8 +26,8 @@
 
 void *aaruf_ecc_cd_init()
 {
-    CdEccContext *context;
-    uint32_t      edc, i, j;
+    CdEccContext *context = NULL;
+    uint32_t edc = 0, i = 0, j = 0;
 
     context = (CdEccContext *)malloc(sizeof(CdEccContext));
 
diff --git a/src/flac.c b/src/flac.c
index 9a2c736..77ade97 100644
--- a/src/flac.c
+++ b/src/flac.c
@@ -37,10 +37,10 @@ static void error_callback(const FLAC__StreamDecoder *decoder, FLAC__StreamDecod
 AARU_EXPORT size_t AARU_CALL aaruf_flac_decode_redbook_buffer(uint8_t *dst_buffer, size_t dst_size,
                                                               const uint8_t *src_buffer, size_t src_size)
 {
-    FLAC__StreamDecoder          *decoder;
-    FLAC__StreamDecoderInitStatus init_status;
+    FLAC__StreamDecoder *decoder = NULL;
+    FLAC__StreamDecoderInitStatus init_status = FLAC__STREAM_DECODER_INIT_STATUS_OK;
     aaru_flac_ctx                *ctx = (aaru_flac_ctx *)malloc(sizeof(aaru_flac_ctx));
-    size_t                        ret_size;
+    size_t ret_size = 0;
 
     memset(ctx, 0, sizeof(aaru_flac_ctx));
 
@@ -148,12 +148,12 @@ AARU_EXPORT size_t AARU_CALL aaruf_flac_encode_redbook_buffer(
     uint32_t min_residual_partition_order, uint32_t max_residual_partition_order, const char *application_id,
     uint32_t application_id_len)
 {
-    FLAC__StreamEncoder          *encoder;
+    FLAC__StreamEncoder *encoder = NULL;
     aaru_flac_ctx                *ctx = (aaru_flac_ctx *)malloc(sizeof(aaru_flac_ctx));
-    FLAC__StreamEncoderInitStatus init_status;
-    size_t                        ret_size;
-    FLAC__int32                  *pcm;
-    int                           i;
+    FLAC__StreamEncoderInitStatus init_status = FLAC__STREAM_ENCODER_INIT_STATUS_OK;
+    size_t ret_size = 0;
+    FLAC__int32 *pcm = NULL;
+    int i = 0;
     int16_t                      *buffer16 = (int16_t *)src_buffer;
     FLAC__StreamMetadata         *metadata[1];
 
diff --git a/src/identify.c b/src/identify.c
index 4ecc3fd..e160b62 100644
--- a/src/identify.c
+++ b/src/identify.c
@@ -30,7 +30,7 @@
  */
 int aaruf_identify(const char *filename)
 {
-    FILE *stream;
+    FILE *stream = NULL;
 
     stream = fopen(filename, "rb");
 
diff --git a/src/open.c b/src/open.c
index 2899041..8b83771 100644
--- a/src/open.c
+++ b/src/open.c
@@ -30,25 +30,25 @@
 
 void *aaruf_open(const char *filepath)
 {
-    aaruformatContext *ctx;
-    int                errorNo;
-    size_t             readBytes;
-    long               pos;
+    aaruformatContext *ctx = NULL;
+    int errorNo = 0;
+    size_t readBytes = 0;
+    long pos = 0;
     IndexHeader        idxHeader;
-    IndexEntry        *idxEntries;
-    uint8_t           *data;
-    uint8_t           *cmpData;
-    uint8_t           *cstData;
-    uint32_t          *cdDdt;
-    uint64_t           crc64;
-    int                i, j, k;
-    uint16_t           e;
+    IndexEntry *idxEntries = NULL;
+    uint8_t *data = NULL;
+    uint8_t *cmpData = NULL;
+    uint8_t *cstData = NULL;
+    uint32_t *cdDdt = NULL;
+    uint64_t crc64 = 0;
+    int i = 0, j = 0, k = 0;
+    uint16_t e = 0;
     uint8_t            lzmaProperties[LZMA_PROPERTIES_LENGTH];
-    size_t             lzmaSize;
+    size_t lzmaSize = 0;
     ChecksumHeader     checksum_header;
-    ChecksumEntry     *checksum_entry;
-    mediaTagEntry     *mediaTag;
-    mediaTagEntry     *oldMediaTag;
+    ChecksumEntry const *checksum_entry = NULL;
+    mediaTagEntry *mediaTag = NULL;
+    mediaTagEntry *oldMediaTag = NULL;
 
     ctx = (aaruformatContext *)malloc(sizeof(aaruformatContext));
     memset(ctx, 0, sizeof(aaruformatContext));
diff --git a/src/read.c b/src/read.c
index d262150..b5c0fe6 100644
--- a/src/read.c
+++ b/src/read.c
@@ -55,18 +55,18 @@ int32_t aaruf_read_media_tag(void *context, uint8_t *data, int32_t tag, uint32_t
 
 int32_t aaruf_read_sector(void *context, uint64_t sectorAddress, uint8_t *data, uint32_t *length)
 {
-    aaruformatContext *ctx;
-    uint64_t           ddtEntry;
-    uint32_t           offsetMask;
-    uint64_t           offset;
-    uint64_t           blockOffset;
-    BlockHeader       *blockHeader;
-    uint8_t           *block;
-    size_t             readBytes;
+    aaruformatContext *ctx = NULL;
+    uint64_t ddtEntry = 0;
+    uint32_t offsetMask = 0;
+    uint64_t offset = 0;
+    uint64_t blockOffset = 0;
+    BlockHeader *blockHeader = NULL;
+    uint8_t *block = NULL;
+    size_t readBytes = 0;
     uint8_t            lzmaProperties[LZMA_PROPERTIES_LENGTH];
-    size_t             lzmaSize;
-    uint8_t           *cmpData;
-    int                errorNo;
+    size_t lzmaSize = 0;
+    uint8_t *cmpData = NULL;
+    int errorNo = 0;
 
     if(context == NULL) return AARUF_ERROR_NOT_AARUFORMAT;
 
@@ -279,14 +279,14 @@ int32_t aaruf_read_track_sector(void *context, uint8_t *data, uint64_t sectorAdd
 
 int32_t aaruf_read_sector_long(void *context, uint64_t sectorAddress, uint8_t *data, uint32_t *length)
 {
-    aaruformatContext *ctx;
-    uint32_t           bareLength;
-    uint32_t           tagLength;
-    uint8_t           *bareData;
-    int32_t            res;
+    aaruformatContext *ctx = NULL;
+    uint32_t bareLength = 0;
+    uint32_t tagLength = 0;
+    uint8_t *bareData = NULL;
+    int32_t res = 0;
     TrackEntry         trk;
-    int                i;
-    bool               trkFound;
+    int i = 0;
+    bool trkFound = false;
 
     if(context == NULL) return AARUF_ERROR_NOT_AARUFORMAT;
 
diff --git a/src/simd.c b/src/simd.c
index ac56bff..e93f16e 100644
--- a/src/simd.c
+++ b/src/simd.c
@@ -126,7 +126,7 @@ int have_avx2()
 #if(defined(__aarch64__) || defined(_M_ARM64) || defined(__arm__) || defined(_M_ARM)) && defined(__APPLE__)
 int have_neon_apple()
 {
-    int    value;
+    int value = 0;
     size_t len = sizeof(int);
     int    ret = sysctlbyname("hw.optional.neon", &value, &len, NULL, 0);
 
@@ -137,7 +137,7 @@ int have_neon_apple()
 
 int have_crc32_apple()
 {
-    int    value;
+    int value = 0;
     size_t len = sizeof(int);
     int    ret = sysctlbyname("hw.optional.crc32", &value, &len, NULL, 0);
 
diff --git a/src/spamsum.c b/src/spamsum.c
index 6686116..0917747 100644
--- a/src/spamsum.c
+++ b/src/spamsum.c
@@ -50,10 +50,9 @@ AARU_EXPORT spamsum_ctx *AARU_CALL aaruf_spamsum_init(void)
 
 AARU_EXPORT int AARU_CALL aaruf_spamsum_update(spamsum_ctx *ctx, const uint8_t *data, uint32_t len)
 {
-    int i;
     if(!ctx || !data) return -1;
 
-    for(i = 0; i < len; i++) fuzzy_engine_step(ctx, data[i]);
+    for (int i = 0; i < len; i++) fuzzy_engine_step(ctx, data[i]);
 
     ctx->total_size += len;
 
@@ -71,7 +70,7 @@ AARU_EXPORT void AARU_CALL aaruf_spamsum_free(spamsum_ctx *ctx)
 
 AARU_LOCAL inline void fuzzy_engine_step(spamsum_ctx *ctx, uint8_t c)
 {
-    uint32_t i;
+    uint32_t i = 0;
     /* At each character we update the rolling hash and the normal hashes.
      * When the rolling hash hits a reset value then we emit a normal hash
      * as a element of the signature and reset the normal hash. */
diff --git a/src/verify.c b/src/verify.c
index 851eff7..5c65c33 100644
--- a/src/verify.c
+++ b/src/verify.c
@@ -24,16 +24,16 @@
 
 int32_t aaruf_verify_image(void *context)
 {
-    aaruformatContext *ctx;
-    uint64_t           crc64;
-    int                i;
+    aaruformatContext *ctx = NULL;
+    uint64_t crc64 = 0;
+    int i = 0;
     IndexHeader        index_header;
-    IndexEntry        *index_entries;
-    size_t             read_bytes;
-    void              *buffer;
-    crc64_ctx         *crc64_context;
+    IndexEntry *index_entries = NULL;
+    size_t read_bytes = 0;
+    void *buffer = NULL;
+    crc64_ctx *crc64_context = NULL;
     BlockHeader        block_header;
-    uint64_t           verified_bytes;
+    uint64_t verified_bytes = 0;
     DdtHeader          ddt_header;
     TracksHeader       tracks_header;
 
@@ -88,7 +88,7 @@ int32_t aaruf_verify_image(void *context)
 
     if(crc64 != index_header.crc64)
     {
-        fprintf(stderr, "Expected index CRC 0x%16llX but got 0x%16lX.\n", index_header.crc64, crc64);
+        fprintf(stderr, "Expected index CRC 0x%16llX but got 0x%16llX.\n", index_header.crc64, crc64);
         free(index_entries);
         return AARUF_ERROR_INVALID_BLOCK_CRC;
     }
@@ -148,7 +148,7 @@ int32_t aaruf_verify_image(void *context)
 
                 if(crc64 != block_header.cmpCrc64)
                 {
-                    fprintf(stderr, "Expected block CRC 0x%16llX but got 0x%16lX.\n", block_header.cmpCrc64, crc64);
+                    fprintf(stderr, "Expected block CRC 0x%16llX but got 0x%16llX.\n", block_header.cmpCrc64, crc64);
                     free(index_entries);
                     return AARUF_ERROR_INVALID_BLOCK_CRC;
                 }
diff --git a/tool/ecc_cd.c b/tool/ecc_cd.c
index b90412a..3ae4516 100644
--- a/tool/ecc_cd.c
+++ b/tool/ecc_cd.c
@@ -25,9 +25,9 @@
 bool check_cd_sector_channel(CdEccContext *context, uint8_t *sector, bool *unknown, bool *has_edc, bool *edc_correct,
                              bool *has_ecc_p, bool *ecc_p_correct, bool *has_ecc_q, bool *ecc_q_correct)
 {
-    int      i;
-    uint32_t storedEdc, edc, calculatedEdc;
-    int      size, pos;
+    int i = 0;
+    uint32_t storedEdc = 0, edc = 0, calculatedEdc = 0;
+    int size = 0, pos = 0;
     uint8_t  zeroaddress[4];
 
     *has_edc       = false;
diff --git a/tool/helpers.c b/tool/helpers.c
index 2fa7442..28c02c6 100644
--- a/tool/helpers.c
+++ b/tool/helpers.c
@@ -25,15 +25,14 @@
 char *byte_array_to_hex_string(const unsigned char *array, int array_size)
 {
     char *hex_string = NULL;
-    int   j;
-    int   i;
+    int j = 0;
 
     hex_string = malloc(array_size * 2 + 1);
 
     if(hex_string == NULL) return NULL;
 
     j = 0;
-    for(i = 0; i < array_size; i++)
+    for (int i = 0; i < array_size; i++)
     {
         hex_string[j] = (array[i] >> 4) + '0';
         if(hex_string[j] > '9') hex_string[j] += 0x7;
diff --git a/tool/identify.c b/tool/identify.c
index 9979d60..4d5c9b5 100644
--- a/tool/identify.c
+++ b/tool/identify.c
@@ -21,7 +21,7 @@
 
 int identify(char *path)
 {
-    int ret;
+    int ret = 0;
 
     ret = aaruf_identify(path);
 
diff --git a/tool/info.c b/tool/info.c
index c02806d..fa9f931 100644
--- a/tool/info.c
+++ b/tool/info.c
@@ -29,12 +29,12 @@
 
 int info(char *path)
 {
-    aaruformatContext *ctx;
-    char              *strBuffer;
+    aaruformatContext *ctx = NULL;
+    char *strBuffer = NULL;
     UErrorCode u_error_code = U_ZERO_ERROR;
-    uint               i, j;
-    mediaTagEntry     *mediaTag;
-    mediaTagEntry     *tmpMediaTag;
+    uint i = 0, j = 0;
+    mediaTagEntry const *mediaTag = NULL;
+    mediaTagEntry const *tmpMediaTag = NULL;
     UChar ustr[128];
 
     ctx = aaruf_open(path);
diff --git a/tool/printhex.c b/tool/printhex.c
index b1f224f..7c25350 100644
--- a/tool/printhex.c
+++ b/tool/printhex.c
@@ -27,16 +27,16 @@ int printhex(unsigned char *array, unsigned int length, int width, bool color)
     char          length_hex[17];
     char          str[256];
     char          format[256];
-    int           rows;
-    int           last;
-    int           offset_length;
+    int rows = 0;
+    int last = 0;
+    int offset_length = 0;
     int           str_length = strlen("Offset");
-    int           i;
-    int           b;
-    int           last_bytes;
-    int           last_spaces;
-    int           j;
-    unsigned char v;
+    int i = 0;
+    int b = 0;
+    int last_bytes = 0;
+    int last_spaces = 0;
+    int j = 0;
+    unsigned char v = 0;
 
     if(array == NULL) return 0;
 
diff --git a/tool/read.c b/tool/read.c
index c848eb9..f908eba 100644
--- a/tool/read.c
+++ b/tool/read.c
@@ -26,10 +26,10 @@
 
 int read(unsigned long long sector_no, char *path)
 {
-    aaruformatContext *ctx;
-    int32_t            res;
-    uint32_t           length;
-    uint8_t           *data;
+    aaruformatContext *ctx = NULL;
+    int32_t res = 0;
+    uint32_t length = 0;
+    uint8_t *data = NULL;
 
     ctx = aaruf_open(path);
 
@@ -76,10 +76,10 @@ int read(unsigned long long sector_no, char *path)
 
 int read_long(unsigned long long sector_no, char *path)
 {
-    aaruformatContext *ctx;
-    int32_t            res;
-    uint32_t           length;
-    uint8_t           *data;
+    aaruformatContext *ctx = NULL;
+    int32_t res = 0;
+    uint32_t length = 0;
+    uint8_t *data = NULL;
 
     ctx = aaruf_open(path);
 
diff --git a/tool/verify.c b/tool/verify.c
index 1af7ba0..d21d0dc 100644
--- a/tool/verify.c
+++ b/tool/verify.c
@@ -25,8 +25,8 @@
 
 int verify(char *path)
 {
-    aaruformatContext *ctx;
-    uint32_t           res;
+    aaruformatContext *ctx = NULL;
+    uint32_t res = 0;
 
     ctx = aaruf_open(path);
 
@@ -50,17 +50,18 @@ int verify(char *path)
 
 int verify_sectors(char *path)
 {
-    aaruformatContext *ctx;
-    uint64_t           s;
-    uint8_t           *buffer;
+    aaruformatContext *ctx = NULL;
+    uint8_t *buffer = NULL;
     uint32_t           buffer_len = 2352;
-    int32_t            res;
-    CdEccContext      *cd_ecc_context;
+    int32_t res = 0;
+    CdEccContext *cd_ecc_context = NULL;
     ctx = aaruf_open(path);
-    bool     verify_result;
-    bool     unknown, has_edc, edc_correct, has_ecc_p, ecc_p_correct, has_ecc_q, ecc_q_correct;
-    uint64_t errors, unknowns;
-    bool     any_error;
+    bool verify_result = false;
+    bool has_edc = false, has_ecc_p = false, ecc_p_correct = false, has_ecc_q = false, ecc_q_correct = false;
+    bool edc_correct = false;
+    bool unknown = false;
+    uint64_t errors = 0, unknowns = 0;
+    bool any_error = false;
 
     if(ctx == NULL)
     {
@@ -79,7 +80,7 @@ int verify_sectors(char *path)
     unknowns       = 0;
     any_error      = false;
 
-    for(s = 0; s < ctx->imageInfo.Sectors; s++)
+    for (uint64_t s = 0; s < ctx->imageInfo.Sectors; s++)
     {
         printf("\rVerifying sector %llu...", s);
         res = aaruf_read_sector_long(ctx, s, buffer, &buffer_len);