diff --git a/jbmc/src/java_bytecode/lazy_goto_functions_map.h b/jbmc/src/java_bytecode/lazy_goto_functions_map.h
index d8af53dc9b5..aaff168b2a6 100644
--- a/jbmc/src/java_bytecode/lazy_goto_functions_map.h
+++ b/jbmc/src/java_bytecode/lazy_goto_functions_map.h
@@ -126,9 +126,12 @@ class lazy_goto_functions_mapt final
            driver_program_can_generate_function_body(name);
   }
 
-  void unload(const key_type &name) const
+  /// Remove the function named \p name from the function map, if it exists.
+  /// \return Returns 0 when \p name was not present, and 1 when \p name was
+  ///   removed.
+  std::size_t unload(const key_type &name) const
   {
-    goto_functions.erase(name);
+    return goto_functions.erase(name);
   }
 
   void ensure_function_loaded(const key_type &name) const
diff --git a/jbmc/src/java_bytecode/lazy_goto_model.cpp b/jbmc/src/java_bytecode/lazy_goto_model.cpp
index 0252346c1dd..c3a183d74fe 100644
--- a/jbmc/src/java_bytecode/lazy_goto_model.cpp
+++ b/jbmc/src/java_bytecode/lazy_goto_model.cpp
@@ -170,7 +170,7 @@ void lazy_goto_modelt::initialize(
   set_up_custom_entry_point(
     language_files,
     symbol_table,
-    [this](const irep_idt &id) { goto_functions.unload(id); },
+    [this](const irep_idt &id) { return goto_functions.unload(id); },
     options,
     false,
     message_handler);
diff --git a/src/goto-programs/goto_functions.h b/src/goto-programs/goto_functions.h
index 01a73e7e625..73f8d06ba1d 100644
--- a/src/goto-programs/goto_functions.h
+++ b/src/goto-programs/goto_functions.h
@@ -66,8 +66,13 @@ class goto_functionst
     return *this;
   }
 
-  /// Remove function from the function map
-  void unload(const irep_idt &name) { function_map.erase(name); }
+  /// Remove the function named \p name from the function map, if it exists.
+  /// \return Returns 0 when \p name was not present, and 1 when \p name was
+  ///   removed.
+  std::size_t unload(const irep_idt &name)
+  {
+    return function_map.erase(name);
+  }
 
   void clear()
   {
diff --git a/src/goto-programs/goto_model.h b/src/goto-programs/goto_model.h
index b5e0c55a839..7debed5795c 100644
--- a/src/goto-programs/goto_model.h
+++ b/src/goto-programs/goto_model.h
@@ -66,7 +66,13 @@ class goto_modelt : public abstract_goto_modelt
     return *this;
   }
 
-  void unload(const irep_idt &name) { goto_functions.unload(name); }
+  /// Remove the function named \p name from the function map, if it exists.
+  /// \return Returns 0 when \p name was not present, and 1 when \p name was
+  ///   removed.
+  std::size_t unload(const irep_idt &name)
+  {
+    return goto_functions.unload(name);
+  }
 
   // Implement the abstract goto model interface:
 
diff --git a/src/goto-programs/initialize_goto_model.cpp b/src/goto-programs/initialize_goto_model.cpp
index 840241c59b5..20e1ada9e8a 100644
--- a/src/goto-programs/initialize_goto_model.cpp
+++ b/src/goto-programs/initialize_goto_model.cpp
@@ -120,7 +120,7 @@ void initialize_from_source_files(
 void set_up_custom_entry_point(
   language_filest &language_files,
   symbol_tablet &symbol_table,
-  const std::function<void(const irep_idt &)> &unload,
+  const std::function<std::size_t(const irep_idt &)> &unload,
   const optionst &options,
   bool try_mode_lookup,
   message_handlert &message_handler)
@@ -213,7 +213,7 @@ goto_modelt initialize_goto_model(
   set_up_custom_entry_point(
     language_files,
     goto_model.symbol_table,
-    [&goto_model](const irep_idt &id) { goto_model.goto_functions.unload(id); },
+    [&goto_model](const irep_idt &id) { return goto_model.unload(id); },
     options,
     true,
     message_handler);
diff --git a/src/goto-programs/initialize_goto_model.h b/src/goto-programs/initialize_goto_model.h
index e0cb1f23112..6925a10e3f5 100644
--- a/src/goto-programs/initialize_goto_model.h
+++ b/src/goto-programs/initialize_goto_model.h
@@ -51,7 +51,7 @@ void initialize_from_source_files(
 void set_up_custom_entry_point(
   language_filest &language_files,
   symbol_tablet &symbol_table,
-  const std::function<void(const irep_idt &)> &unload,
+  const std::function<std::size_t(const irep_idt &)> &unload,
   const optionst &options,
   bool try_mode_lookup,
   message_handlert &message_handler);