diff --git a/src/impl/list_ports/list_ports_linux.cc b/src/impl/list_ports/list_ports_linux.cc
index 9779d5eb..bd67fff3 100644
--- a/src/impl/list_ports/list_ports_linux.cc
+++ b/src/impl/list_ports/list_ports_linux.cc
@@ -54,16 +54,16 @@ glob(const vector<string>& patterns)
 
     glob_t glob_results;
 
-    int glob_retval = glob(patterns[0].c_str(), 0, NULL, &glob_results);
+    glob(patterns[0].c_str(), 0, NULL, &glob_results);
 
     vector<string>::const_iterator iter = patterns.begin();
 
     while(++iter != patterns.end())
     {
-        glob_retval = glob(iter->c_str(), GLOB_APPEND, NULL, &glob_results);
+        glob(iter->c_str(), GLOB_APPEND, NULL, &glob_results);
     }
 
-    for(int path_index = 0; path_index < glob_results.gl_pathc; path_index++)
+    for(unsigned int path_index = 0; path_index < glob_results.gl_pathc; path_index++)
     {
         paths_found.push_back(glob_results.gl_pathv[path_index]);
     }
@@ -243,7 +243,7 @@ format(const char* format, ...)
         {
             done = true;
         }
-        else if( return_value >= buffer_size_bytes )
+        else if(static_cast<unsigned int>(return_value) >= buffer_size_bytes)
         {
             // Realloc and try again.