diff --git a/jbmc/src/java_bytecode/jar_file.cpp b/jbmc/src/java_bytecode/jar_file.cpp
index 4bab160e83d..b1ae84ea9fa 100644
--- a/jbmc/src/java_bytecode/jar_file.cpp
+++ b/jbmc/src/java_bytecode/jar_file.cpp
@@ -80,7 +80,7 @@ optionalt<std::string> jar_filet::get_entry(const std::string &name)
 
 static bool is_space(const char ch)
 {
-  return std::isspace(ch);
+  return std::isspace(ch) != 0;
 }
 
 /// Remove leading and trailing whitespace characters from string
diff --git a/src/util/unicode.cpp b/src/util/unicode.cpp
index 6f329e2203c..0a4b9ea47fb 100644
--- a/src/util/unicode.cpp
+++ b/src/util/unicode.cpp
@@ -23,7 +23,7 @@ Author: Daniel Kroening, kroening@kroening.com
 bool is_little_endian_arch()
 {
   uint32_t i=1;
-  return reinterpret_cast<uint8_t &>(i);
+  return reinterpret_cast<uint8_t &>(i) != 0;
 }
 
 #define BUFSIZE 100