diff --git a/src/Main/fg_props.cxx b/src/Main/fg_props.cxx
index 8eefb8c49..8f3036776 100644
--- a/src/Main/fg_props.cxx
+++ b/src/Main/fg_props.cxx
@@ -668,7 +668,7 @@ fgGetInt (const char * name, int defaultValue)
   return globals->get_props()->getIntValue(name, defaultValue);
 }
 
-int
+long
 fgGetLong (const char * name, long defaultValue)
 {
   return globals->get_props()->getLongValue(name, defaultValue);
diff --git a/src/Main/fg_props.hxx b/src/Main/fg_props.hxx
index eb9af1dfe..023d4dbbf 100644
--- a/src/Main/fg_props.hxx
+++ b/src/Main/fg_props.hxx
@@ -299,7 +299,7 @@ inline int fgGetInt (const std::string & name, int defaultValue = 0)
  *        does not exist.
  * @return The property's value as a long, or the default value provided.
  */
-extern int fgGetLong (const char * name, long defaultValue = 0L);
+extern long fgGetLong (const char * name, long defaultValue = 0L);
 
 /**
  * Get a long value for a property.
@@ -315,7 +315,7 @@ extern int fgGetLong (const char * name, long defaultValue = 0L);
  *        does not exist.
  * @return The property's value as a long, or the default value provided.
  */
-inline int fgGetLong (const std::string & name, long defaultValue = 0L)
+inline long fgGetLong (const std::string & name, long defaultValue = 0L)
 {
     return fgGetLong( name.c_str(), defaultValue );
 }