* Added -Wextra and -Wshadow compiler options, to enforce extra warnings, and

  fixed the code necessary to comply with these flags
* Fixed a bug introduced in the 1.0 release, that caused last modified time
  not to be reported to callbacks
* Changed the semantics of the put data callback, to only make the callback
  enough times to get enough data to satisfy the content length
* Fixed the error status when curl doesn't get a valid HTTP response from
  S3 to be S3StatusConnectionFailed instead of S3StatusHttpErrorUnknown
* Fixed a bug where S3_runall_request_context would stop even though a
  callback had added another request
* libs3.h doesn't need sys/time.h anymore, it just needs sys/select.h
* Some minor documentation enhancements

7 files changed, 133 insertions, 94 deletions

diff --git a/src/bucket.c b/src/bucket.c
index a2446df..ccedd0b 100644
--- a/src/bucket.c
+++ b/src/bucket.c
@@ -532,7 +532,7 @@ static S3Status listBucketXmlCallback(const char *elementPath,
                          lbData->commonPrefixLens[which] - 1,
                          "%.*s", dataLen, data);
             if (lbData->commonPrefixLens[which] >=
-                sizeof(lbData->commonPrefixes[which])) {
+                (int) sizeof(lbData->commonPrefixes[which])) {
                 return S3StatusXmlParseFailure;
             }
         }
diff --git a/src/request.c b/src/request.c
index 79837fa..33eac35 100644
--- a/src/request.c
+++ b/src/request.c
@@ -172,19 +172,31 @@ static size_t curl_read_func(void *ptr, size_t size, size_t nmemb, void *data)
         return CURL_READFUNC_ABORT;
     }
 
-    if (request->toS3Callback) {
-        int ret = (*(request->toS3Callback))
-            (len, (char *) ptr, request->callbackData);
-        if (ret < 0) {
-            request->status = S3StatusAbortedByCallback;
-            return CURL_READFUNC_ABORT;
-        }
-        else {
-            return ret;
-        }
+    // If there is no data callback, or the data callback has already returned
+    // contentLength bytes, return 0;
+    if (!request->toS3Callback || !request->toS3CallbackBytesRemaining) {
+        return 0;
+    }
+    
+    // Don't tell the callback that we are willing to accept more data than we
+    // really are
+    if (len > request->toS3CallbackBytesRemaining) {
+        len = request->toS3CallbackBytesRemaining;
+    }
+
+    // Otherwise, make the data callback
+    int ret = (*(request->toS3Callback))
+        (len, (char *) ptr, request->callbackData);
+    if (ret < 0) {
+        request->status = S3StatusAbortedByCallback;
+        return CURL_READFUNC_ABORT;
     }
     else {
-        return 0;
+        if (ret > request->toS3CallbackBytesRemaining) {
+            ret = request->toS3CallbackBytesRemaining;
+        }
+        request->toS3CallbackBytesRemaining -= ret;
+        return ret;
     }
 }
 
@@ -253,7 +265,7 @@ static S3Status compose_amz_headers(const RequestParams *params,
         len += snprintf(&(values->amzHeadersRaw[len]),                  \
                         sizeof(values->amzHeadersRaw) - len,            \
                         format, __VA_ARGS__);                           \
-        if (len >= sizeof(values->amzHeadersRaw)) {                     \
+        if (len >= (int) sizeof(values->amzHeadersRaw)) {               \
             return S3StatusMetaDataHeadersTooLong;                      \
         }                                                               \
         while ((len > 0) && (values->amzHeadersRaw[len - 1] == ' ')) {  \
@@ -266,7 +278,7 @@ static S3Status compose_amz_headers(const RequestParams *params,
     do {                                                                \
         values->amzHeaders[values->amzHeadersCount++] =                 \
             &(values->amzHeadersRaw[len]);                              \
-        if ((len + l) >= sizeof(values->amzHeadersRaw)) {               \
+        if ((len + l) >= (int) sizeof(values->amzHeadersRaw)) {         \
             return S3StatusMetaDataHeadersTooLong;                      \
         }                                                               \
         int todo = l;                                                   \
@@ -362,7 +374,7 @@ static S3Status compose_standard_headers(const RequestParams *params,
             /* Compose header, make sure it all fit */                      \
             int len = snprintf(values-> destField,                          \
                                sizeof(values-> destField), fmt, val);       \
-            if (len >= sizeof(values-> destField)) {                        \
+            if (len >= (int) sizeof(values-> destField)) {                  \
                 return tooLongError;                                        \
             }                                                               \
             /* Now remove the whitespace at the end */                      \
@@ -392,7 +404,7 @@ static S3Status compose_standard_headers(const RequestParams *params,
             /* Compose header, make sure it all fit */                      \
             int len = snprintf(values-> destField,                          \
                                sizeof(values-> destField), fmt, val);       \
-            if (len >= sizeof(values-> destField)) {                        \
+            if (len >= (int) sizeof(values-> destField)) {                  \
                 return tooLongError;                                        \
             }                                                               \
             /* Now remove the whitespace at the end */                      \
@@ -732,7 +744,7 @@ static S3Status compose_uri(Request *request, const RequestParams *params,
         len += snprintf(&(request->uri[len]),           \
                         sizeof(request->uri) - len,     \
                         fmt, __VA_ARGS__);              \
-        if (len >= sizeof(request->uri)) {              \
+        if (len >= (int) sizeof(request->uri)) {        \
             return S3StatusUriTooLong;                  \
         }                                               \
     } while (0)
@@ -990,6 +1002,8 @@ static S3Status request_get(const RequestParams *params,
 
     request->toS3Callback = params->toS3Callback;
 
+    request->toS3CallbackBytesRemaining = params->toS3CallbackTotalSize;
+
     request->fromS3Callback = params->fromS3Callback;
 
     request->completeCallback = params->completeCallback;
@@ -1186,6 +1200,11 @@ void request_finish(Request *request)
             ((request->httpResponseCode < 200) ||
              (request->httpResponseCode > 299))) {
             switch (request->httpResponseCode) {
+            case 0:
+                // This happens if the request never got any HTTP response
+                // headers at all, we call this a ConnectionFailed error
+                request->status = S3StatusConnectionFailed;
+                break;
             case 100: // Some versions of libcurl erroneously set HTTP
                       // status to this
                 break;
diff --git a/src/request_context.c b/src/request_context.c
index d049778..bc6af99 100644
--- a/src/request_context.c
+++ b/src/request_context.c
@@ -160,6 +160,9 @@ S3Status S3_runonce_request_context(S3RequestContext *requestContext,
             // Finish the request, ensuring that all callbacks have been made,
             // and also releases the request
             request_finish(request);
+            // Now, since a callback was made, there may be new requests 
+            // queued up to be performed immediately, so do so
+            status = CURLM_CALL_MULTI_PERFORM;
         }
     } while (status == CURLM_CALL_MULTI_PERFORM);
 
diff --git a/src/response_headers_handler.c b/src/response_headers_handler.c
index cbaa4bf..14e14a0 100644
--- a/src/response_headers_handler.c
+++ b/src/response_headers_handler.c
@@ -195,10 +195,10 @@ void response_headers_handler_done(ResponseHeadersHandler *handler, CURL *curl)
 {
     // Now get the last modification time from curl, since it's easiest to let
     // curl parse it
+    time_t lastModified;
     if (curl_easy_getinfo
-        (curl, CURLINFO_FILETIME, 
-         &(handler->responseProperties.lastModified)) != CURLE_OK) {
-        handler->responseProperties.lastModified = -1;
+        (curl, CURLINFO_FILETIME, &lastModified) == CURLE_OK) {
+        handler->responseProperties.lastModified = lastModified;
     }
     
     handler->done = 1;
diff --git a/src/s3.c b/src/s3.c
index 55ee2ac..62e83af 100644
--- a/src/s3.c
+++ b/src/s3.c
@@ -546,7 +546,7 @@ static int convert_simple_acl(char *aclXml, char *ownerId,
     } while (0)
 
 #define COPY_STRING(field)                              \
-    COPY_STRING_MAXLEN(field, (sizeof(field) - 1))
+    COPY_STRING_MAXLEN(field, (int) (sizeof(field) - 1))
 
     while (1) {
         SKIP_SPACE(0);
@@ -674,6 +674,8 @@ static struct option longOptionsG[] =
 static S3Status responsePropertiesCallback
     (const S3ResponseProperties *properties, void *callbackData)
 {
+    (void) callbackData;
+
     if (!showResponsePropertiesG) {
         return S3StatusOK;
     }
@@ -719,6 +721,8 @@ static void responseCompleteCallback(S3Status status,
                                      const S3ErrorDetails *error, 
                                      void *callbackData)
 {
+    (void) callbackData;
+
     statusG = status;
     // Compose the error details message now, although we might not use it.
     // Can't just save a pointer to [error] since it's not guaranteed to last
@@ -846,18 +850,18 @@ static void list_service(int allDetails)
 
 // test bucket ---------------------------------------------------------------
 
-static void test_bucket(int argc, char **argv, int optind)
+static void test_bucket(int argc, char **argv, int optindex)
 {
     // test bucket
-    if (optind == argc) {
+    if (optindex == argc) {
         fprintf(stderr, "\nERROR: Missing parameter: bucket\n");
         usageExit(stderr);
     }
 
-    const char *bucketName = argv[optind++];
+    const char *bucketName = argv[optindex++];
 
-    if (optind != argc) {
-        fprintf(stderr, "\nERROR: Extraneous parameter: %s\n", argv[optind]);
+    if (optindex != argc) {
+        fprintf(stderr, "\nERROR: Extraneous parameter: %s\n", argv[optindex]);
         usageExit(stderr);
     }
 
@@ -910,14 +914,14 @@ static void test_bucket(int argc, char **argv, int optind)
 
 // create bucket -------------------------------------------------------------
 
-static void create_bucket(int argc, char **argv, int optind)
+static void create_bucket(int argc, char **argv, int optindex)
 {
-    if (optind == argc) {
+    if (optindex == argc) {
         fprintf(stderr, "\nERROR: Missing parameter: bucket\n");
         usageExit(stderr);
     }
 
-    const char *bucketName = argv[optind++];
+    const char *bucketName = argv[optindex++];
 
     if (!forceG && (S3_validate_bucket_name
                     (bucketName, S3UriStyleVirtualHost) != S3StatusOK)) {
@@ -931,8 +935,8 @@ static void create_bucket(int argc, char **argv, int optind)
 
     const char *locationConstraint = 0;
     S3CannedAcl cannedAcl = S3CannedAclPrivate;
-    while (optind < argc) {
-        char *param = argv[optind++];
+    while (optindex < argc) {
+        char *param = argv[optindex++];
         if (!strncmp(param, LOCATION_PREFIX, LOCATION_PREFIX_LEN)) {
             locationConstraint = &(param[LOCATION_PREFIX_LEN]);
         }
@@ -987,17 +991,17 @@ static void create_bucket(int argc, char **argv, int optind)
 
 // delete bucket -------------------------------------------------------------
 
-static void delete_bucket(int argc, char **argv, int optind)
+static void delete_bucket(int argc, char **argv, int optindex)
 {
-    if (optind == argc) {
+    if (optindex == argc) {
         fprintf(stderr, "\nERROR: Missing parameter: bucket\n");
         usageExit(stderr);
     }
 
-    const char *bucketName = argv[optind++];
+    const char *bucketName = argv[optindex++];
 
-    if (optind != argc) {
-        fprintf(stderr, "\nERROR: Extraneous parameter: %s\n", argv[optind]);
+    if (optindex != argc) {
+        fprintf(stderr, "\nERROR: Extraneous parameter: %s\n", argv[optindex]);
         usageExit(stderr);
     }
 
@@ -1205,9 +1209,9 @@ static void list_bucket(const char *bucketName, const char *prefix,
 }
 
 
-static void list(int argc, char **argv, int optind)
+static void list(int argc, char **argv, int optindex)
 {
-    if (optind == argc) {
+    if (optindex == argc) {
         list_service(0);
         return;
     }
@@ -1216,8 +1220,8 @@ static void list(int argc, char **argv, int optind)
 
     const char *prefix = 0, *marker = 0, *delimiter = 0;
     int maxkeys = 0, allDetails = 0;
-    while (optind < argc) {
-        char *param = argv[optind++];
+    while (optindex < argc) {
+        char *param = argv[optindex++];
         if (!strncmp(param, PREFIX_PREFIX, PREFIX_PREFIX_LEN)) {
             prefix = &(param[PREFIX_PREFIX_LEN]);
         }
@@ -1261,10 +1265,12 @@ static void list(int argc, char **argv, int optind)
 
 // delete object -------------------------------------------------------------
 
-static void delete_object(int argc, char **argv, int optind)
+static void delete_object(int argc, char **argv, int optindex)
 {
+    (void) argc;
+
     // Split bucket/key
-    char *slash = argv[optind];
+    char *slash = argv[optindex];
 
     // We know there is a slash in there, put_object is only called if so
     while (*slash && (*slash != '/')) {
@@ -1272,7 +1278,7 @@ static void delete_object(int argc, char **argv, int optind)
     }
     *slash++ = 0;
 
-    const char *bucketName = argv[optind++];
+    const char *bucketName = argv[optindex++];
     const char *key = slash;
 
     S3_init();
@@ -1325,8 +1331,8 @@ static int putObjectDataCallback(int bufferSize, char *buffer,
     int ret = 0;
 
     if (data->contentLength) {
-        int toRead = ((data->contentLength > bufferSize) ?
-                      bufferSize : data->contentLength);
+        int toRead = ((data->contentLength > (unsigned) bufferSize) ?
+                      (unsigned) bufferSize : data->contentLength);
         if (data->gb) {
             growbuffer_read(&(data->gb), toRead, &ret, buffer);
         }
@@ -1352,26 +1358,26 @@ static int putObjectDataCallback(int bufferSize, char *buffer,
 }
 
 
-static void put_object(int argc, char **argv, int optind)
+static void put_object(int argc, char **argv, int optindex)
 {
-    if (optind == argc) {
+    if (optindex == argc) {
         fprintf(stderr, "\nERROR: Missing parameter: bucket/key\n");
         usageExit(stderr);
     }
 
     // Split bucket/key
-    char *slash = argv[optind];
+    char *slash = argv[optindex];
     while (*slash && (*slash != '/')) {
         slash++;
     }
     if (!*slash || !*(slash + 1)) {
         fprintf(stderr, "\nERROR: Invalid bucket/key name: %s\n",
-                argv[optind]);
+                argv[optindex]);
         usageExit(stderr);
     }
     *slash++ = 0;
 
-    const char *bucketName = argv[optind++];
+    const char *bucketName = argv[optindex++];
     const char *key = slash;
 
     const char *filename = 0;
@@ -1384,8 +1390,8 @@ static void put_object(int argc, char **argv, int optind)
     S3NameValue metaProperties[S3_MAX_METADATA_COUNT];
     int noStatus = 0;
 
-    while (optind < argc) {
-        char *param = argv[optind++];
+    while (optindex < argc) {
+        char *param = argv[optindex++];
         if (!strncmp(param, FILENAME_PREFIX, FILENAME_PREFIX_LEN)) {
             filename = &(param[FILENAME_PREFIX_LEN]);
         }
@@ -1523,7 +1529,7 @@ static void put_object(int argc, char **argv, int optind)
                     exit(-1);
                 }
                 contentLength += amtRead;
-                if (amtRead < sizeof(buffer)) {
+                if (amtRead < (int) sizeof(buffer)) {
                     break;
                 }
             }
@@ -1591,47 +1597,47 @@ static void put_object(int argc, char **argv, int optind)
 
 // copy object ---------------------------------------------------------------
 
-static void copy_object(int argc, char **argv, int optind)
+static void copy_object(int argc, char **argv, int optindex)
 {
-    if (optind == argc) {
+    if (optindex == argc) {
         fprintf(stderr, "\nERROR: Missing parameter: source bucket/key\n");
         usageExit(stderr);
     }
 
     // Split bucket/key
-    char *slash = argv[optind];
+    char *slash = argv[optindex];
     while (*slash && (*slash != '/')) {
         slash++;
     }
     if (!*slash || !*(slash + 1)) {
         fprintf(stderr, "\nERROR: Invalid source bucket/key name: %s\n",
-                argv[optind]);
+                argv[optindex]);
         usageExit(stderr);
     }
     *slash++ = 0;
 
-    const char *sourceBucketName = argv[optind++];
+    const char *sourceBucketName = argv[optindex++];
     const char *sourceKey = slash;
 
-    if (optind == argc) {
+    if (optindex == argc) {
         fprintf(stderr, "\nERROR: Missing parameter: "
                 "destination bucket/key\n");
         usageExit(stderr);
     }
 
     // Split bucket/key
-    slash = argv[optind];
+    slash = argv[optindex];
     while (*slash && (*slash != '/')) {
         slash++;
     }
     if (!*slash || !*(slash + 1)) {
         fprintf(stderr, "\nERROR: Invalid destination bucket/key name: %s\n",
-                argv[optind]);
+                argv[optindex]);
         usageExit(stderr);
     }
     *slash++ = 0;
 
-    const char *destinationBucketName = argv[optind++];
+    const char *destinationBucketName = argv[optindex++];
     const char *destinationKey = slash;
 
     const char *cacheControl = 0, *contentType = 0;
@@ -1642,8 +1648,8 @@ static void copy_object(int argc, char **argv, int optind)
     S3NameValue metaProperties[S3_MAX_METADATA_COUNT];
     int anyPropertiesSet = 0;
 
-    while (optind < argc) {
-        char *param = argv[optind++];
+    while (optindex < argc) {
+        char *param = argv[optindex++];
         if (!strncmp(param, CACHE_CONTROL_PREFIX, 
                           CACHE_CONTROL_PREFIX_LEN)) {
             cacheControl = &(param[CACHE_CONTROL_PREFIX_LEN]);
@@ -1790,30 +1796,31 @@ static S3Status getObjectDataCallback(int bufferSize, const char *buffer,
 
     size_t wrote = fwrite(buffer, 1, bufferSize, outfile);
     
-    return (wrote < bufferSize) ? S3StatusAbortedByCallback : S3StatusOK;
+    return ((wrote < (size_t) bufferSize) ? 
+            S3StatusAbortedByCallback : S3StatusOK);
 }
 
 
-static void get_object(int argc, char **argv, int optind)
+static void get_object(int argc, char **argv, int optindex)
 {
-    if (optind == argc) {
+    if (optindex == argc) {
         fprintf(stderr, "\nERROR: Missing parameter: bucket/key\n");
         usageExit(stderr);
     }
 
     // Split bucket/key
-    char *slash = argv[optind];
+    char *slash = argv[optindex];
     while (*slash && (*slash != '/')) {
         slash++;
     }
     if (!*slash || !*(slash + 1)) {
         fprintf(stderr, "\nERROR: Invalid bucket/key name: %s\n",
-                argv[optind]);
+                argv[optindex]);
         usageExit(stderr);
     }
     *slash++ = 0;
 
-    const char *bucketName = argv[optind++];
+    const char *bucketName = argv[optindex++];
     const char *key = slash;
 
     const char *filename = 0;
@@ -1821,8 +1828,8 @@ static void get_object(int argc, char **argv, int optind)
     const char *ifMatch = 0, *ifNotMatch = 0;
     uint64_t startByte = 0, byteCount = 0;
 
-    while (optind < argc) {
-        char *param = argv[optind++];
+    while (optindex < argc) {
+        char *param = argv[optindex++];
         if (!strncmp(param, FILENAME_PREFIX, FILENAME_PREFIX_LEN)) {
             filename = &(param[FILENAME_PREFIX_LEN]);
         }
@@ -1946,9 +1953,9 @@ static void get_object(int argc, char **argv, int optind)
 
 // head object ---------------------------------------------------------------
 
-static void head_object(int argc, char **argv, int optind)
+static void head_object(int argc, char **argv, int optindex)
 {
-    if (optind == argc) {
+    if (optindex == argc) {
         fprintf(stderr, "\nERROR: Missing parameter: bucket/key\n");
         usageExit(stderr);
     }
@@ -1957,23 +1964,23 @@ static void head_object(int argc, char **argv, int optind)
     showResponsePropertiesG = 1;
 
     // Split bucket/key
-    char *slash = argv[optind];
+    char *slash = argv[optindex];
 
     while (*slash && (*slash != '/')) {
         slash++;
     }
     if (!*slash || !*(slash + 1)) {
         fprintf(stderr, "\nERROR: Invalid bucket/key name: %s\n",
-                argv[optind]);
+                argv[optindex]);
         usageExit(stderr);
     }
     *slash++ = 0;
 
-    const char *bucketName = argv[optind++];
+    const char *bucketName = argv[optindex++];
     const char *key = slash;
 
-    if (optind != argc) {
-        fprintf(stderr, "\nERROR: Extraneous parameter: %s\n", argv[optind]);
+    if (optindex != argc) {
+        fprintf(stderr, "\nERROR: Extraneous parameter: %s\n", argv[optindex]);
         usageExit(stderr);
     }
 
@@ -2009,18 +2016,18 @@ static void head_object(int argc, char **argv, int optind)
 
 // get acl -------------------------------------------------------------------
 
-void get_acl(int argc, char **argv, int optind)
+void get_acl(int argc, char **argv, int optindex)
 {
-    if (optind == argc) {
+    if (optindex == argc) {
         fprintf(stderr, "\nERROR: Missing parameter: bucket[/key]\n");
         usageExit(stderr);
     }
 
-    const char *bucketName = argv[optind];
+    const char *bucketName = argv[optindex];
     const char *key = 0;
 
     // Split bucket/key
-    char *slash = argv[optind++];
+    char *slash = argv[optindex++];
     while (*slash && (*slash != '/')) {
         slash++;
     }
@@ -2034,8 +2041,8 @@ void get_acl(int argc, char **argv, int optind)
 
     const char *filename = 0;
 
-    while (optind < argc) {
-        char *param = argv[optind++];
+    while (optindex < argc) {
+        char *param = argv[optindex++];
         if (!strncmp(param, FILENAME_PREFIX, FILENAME_PREFIX_LEN)) {
             filename = &(param[FILENAME_PREFIX_LEN]);
         }
@@ -2172,18 +2179,18 @@ void get_acl(int argc, char **argv, int optind)
 
 // set acl -------------------------------------------------------------------
 
-void set_acl(int argc, char **argv, int optind)
+void set_acl(int argc, char **argv, int optindex)
 {
-    if (optind == argc) {
+    if (optindex == argc) {
         fprintf(stderr, "\nERROR: Missing parameter: bucket[/key]\n");
         usageExit(stderr);
     }
 
-    const char *bucketName = argv[optind];
+    const char *bucketName = argv[optindex];
     const char *key = 0;
 
     // Split bucket/key
-    char *slash = argv[optind++];
+    char *slash = argv[optindex++];
     while (*slash && (*slash != '/')) {
         slash++;
     }
@@ -2197,8 +2204,8 @@ void set_acl(int argc, char **argv, int optind)
 
     const char *filename = 0;
 
-    while (optind < argc) {
-        char *param = argv[optind++];
+    while (optindex < argc) {
+        char *param = argv[optindex++];
         if (!strncmp(param, FILENAME_PREFIX, FILENAME_PREFIX_LEN)) {
             filename = &(param[FILENAME_PREFIX_LEN]);
         }
@@ -2276,8 +2283,8 @@ int main(int argc, char **argv)
 {
     // Parse args
     while (1) {
-        int index = 0;
-        int c = getopt_long(argc, argv, "fhusr:", longOptionsG, &index);
+        int idx = 0;
+        int c = getopt_long(argc, argv, "fhusr:", longOptionsG, &idx);
 
         if (c == -1) {
             // End of options
diff --git a/src/simplexml.c b/src/simplexml.c
index 12eda26..bd8616b 100644
--- a/src/simplexml.c
+++ b/src/simplexml.c
@@ -47,6 +47,8 @@
 
 static xmlEntityPtr saxGetEntity(void *user_data, const xmlChar *name)
 {
+    (void) user_data;
+
     return xmlGetPredefinedEntity(name);
 }
 
@@ -54,6 +56,8 @@ static xmlEntityPtr saxGetEntity(void *user_data, const xmlChar *name)
 static void saxStartElement(void *user_data, const xmlChar *nameUtf8,
                             const xmlChar **attr)
 {
+    (void) attr;
+
     SimpleXml *simpleXml = (SimpleXml *) user_data;
 
     if (simpleXml->status != S3StatusOK) {
@@ -67,7 +71,7 @@ static void saxStartElement(void *user_data, const xmlChar *nameUtf8,
     int len = strlen(name);
 
     if ((simpleXml->elementPathLen + len + 1) >= 
-        sizeof(simpleXml->elementPath)) {
+        (int) sizeof(simpleXml->elementPath)) {
         // Cannot handle this element, stop!
         simpleXml->status = S3StatusXmlParseFailure;
         return;
@@ -83,6 +87,8 @@ static void saxStartElement(void *user_data, const xmlChar *nameUtf8,
 
 static void saxEndElement(void *user_data, const xmlChar *name)
 {
+    (void) name;
+
     SimpleXml *simpleXml = (SimpleXml *) user_data;
 
     if (simpleXml->status != S3StatusOK) {
@@ -117,6 +123,8 @@ static void saxCharacters(void *user_data, const xmlChar *ch, int len)
 
 static void saxError(void *user_data, const char *msg, ...)
 {
+    (void) msg;
+
     SimpleXml *simpleXml = (SimpleXml *) user_data;
 
     if (simpleXml->status != S3StatusOK) {
diff --git a/src/testsimplexml.c b/src/testsimplexml.c
index 7210074..57fba7d 100644
--- a/src/testsimplexml.c
+++ b/src/testsimplexml.c
@@ -33,6 +33,8 @@
 static S3Status simpleXmlCallback(const char *elementPath, const char *data,
                                   int dataLen, void *callbackData)
 {
+    (void) callbackData;
+
     printf("[%s]: [%.*s]\n", elementPath, dataLen, data);
 
     return S3StatusOK;