diff --git a/compiler/Generator.cs b/compiler/Generator.cs
index 82a482d..f565224 100644
--- a/compiler/Generator.cs
+++ b/compiler/Generator.cs
@@ -14,6 +14,9 @@ public sealed class Generator(List<TypedNodeDefinitionFunc> functions, ModuleGra
 
     private string Emit()
     {
+        foreach (var (i, structType) in moduleGraph.GetModules().SelectMany(x => x.GetCustomTypes().OfType<NubTypeStruct>().Index()))
+            structTypeNames[structType] = $"s{i}";
+
         writer.WriteLine("""
                          #include <float.h>
                          #include <stdarg.h>
@@ -28,9 +31,6 @@ public sealed class Generator(List<TypedNodeDefinitionFunc> functions, ModuleGra
 
                          """);
 
-        foreach (var (i, structType) in moduleGraph.GetModules().SelectMany(x => x.GetCustomTypes().OfType<NubTypeStruct>().Index()))
-            structTypeNames[structType] = $"s{i}";
-
         foreach (var typeName in structTypeNames)
             writer.WriteLine($"struct {typeName.Value};");
 
@@ -45,30 +45,55 @@ public sealed class Generator(List<TypedNodeDefinitionFunc> functions, ModuleGra
                 foreach (var field in typeName.Key.Fields)
                     writer.WriteLine($"{CType(field.Type, field.Name)};");
             }
-
             writer.WriteLine("};");
         }
 
         writer.WriteLine();
 
-        foreach (var node in functions)
+        foreach (var module in moduleGraph.GetModules())
         {
-            var parameters = node.Parameters.Select(x => CType(x.Type, x.Name.Ident));
-            writer.WriteLine($"{CType(node.ReturnType, node.Name.Ident)}({string.Join(", ", parameters)});");
+            foreach (var (name, type) in module.GetIdentifierTypes())
+            {
+                if (type is NubTypeFunc fn)
+                {
+                    if (!functions.Any(x => x.GetMangledName() == SymbolNameGen.Exported(module.Name, name, type)))
+                        writer.Write("extern ");
+
+                    writer.WriteLine($"{CType(fn.ReturnType)} {SymbolNameGen.Exported(module.Name, name, type)}({string.Join(", ", fn.Parameters.Select(p => CType(p)))});");
+                }
+                else
+                {
+                    writer.WriteLine($"{CType(type)} {SymbolNameGen.Exported(module.Name, name, type)};");
+                }
+            }
         }
 
         writer.WriteLine();
 
-        foreach (var node in functions)
+        var main = functions.FirstOrDefault(x => x.Module == "main" && x.Name.Ident == "main");
+
+        if (main != null)
         {
-            var parameters = node.Parameters.Select(x => CType(x.Type, x.Name.Ident));
-            writer.WriteLine($"{CType(node.ReturnType, node.Name.Ident)}({string.Join(", ", parameters)})");
+            writer.WriteLine("int main(int argc, char *argv[])");
             writer.WriteLine("{");
             using (writer.Indent())
             {
-                EmitStatement(node.Body);
+                writer.WriteLine($"return {main.GetMangledName()}();");
             }
+            writer.WriteLine("}");
+        }
 
+        writer.WriteLine();
+
+        foreach (var function in functions)
+        {
+            var parameters = function.Parameters.Select(x => CType(x.Type, x.Name.Ident));
+            writer.WriteLine($"{CType(function.ReturnType, function.GetMangledName())}({string.Join(", ", parameters)})");
+            writer.WriteLine("{");
+            using (writer.Indent())
+            {
+                EmitStatement(function.Body);
+            }
             writer.WriteLine("}");
             writer.WriteLine();
         }
@@ -114,7 +139,6 @@ public sealed class Generator(List<TypedNodeDefinitionFunc> functions, ModuleGra
             foreach (var statement in node.Statements)
                 EmitStatement(statement);
         }
-
         writer.WriteLine("}");
     }
 
@@ -153,7 +177,6 @@ public sealed class Generator(List<TypedNodeDefinitionFunc> functions, ModuleGra
         {
             EmitStatement(statement.ThenBlock);
         }
-
         writer.WriteLine("}");
 
         if (statement.ElseBlock != null)
@@ -169,7 +192,6 @@ public sealed class Generator(List<TypedNodeDefinitionFunc> functions, ModuleGra
             {
                 EmitStatement(statement.ElseBlock);
             }
-
             writer.WriteLine("}");
         }
     }
@@ -183,7 +205,6 @@ public sealed class Generator(List<TypedNodeDefinitionFunc> functions, ModuleGra
         {
             EmitStatement(statement.Block);
         }
-
         writer.WriteLine("}");
     }
 
@@ -199,7 +220,7 @@ public sealed class Generator(List<TypedNodeDefinitionFunc> functions, ModuleGra
             TypedNodeExpressionStructLiteral expression => EmitExpressionStructLiteral(expression),
             TypedNodeExpressionMemberAccess expression => EmitExpressionMemberAccess(expression),
             TypedNodeExpressionLocalIdent expression => expression.Value.Ident,
-            TypedNodeExpressionModuleIdent expression => expression.Value.Ident,
+            TypedNodeExpressionModuleIdent expression => SymbolNameGen.Exported(expression.Module.Ident, expression.Value.Ident, expression.Type),
             TypedNodeExpressionFuncCall expression => EmitExpressionFuncCall(expression),
             _ => throw new ArgumentOutOfRangeException(nameof(node), node, null)
         };
diff --git a/compiler/ModuleGraph.cs b/compiler/ModuleGraph.cs
index 1704940..70cad75 100644
--- a/compiler/ModuleGraph.cs
+++ b/compiler/ModuleGraph.cs
@@ -24,11 +24,16 @@ public class ModuleGraph(Dictionary<string, ModuleGraph.Module> modules)
         private readonly Dictionary<string, NubType> customTypes = new();
         private readonly Dictionary<string, NubType> identifierTypes = new();
 
-        public List<NubType> GetCustomTypes()
+        public IReadOnlyList<NubType> GetCustomTypes()
         {
             return customTypes.Values.ToList();
         }
 
+        public IReadOnlyDictionary<string, NubType> GetIdentifierTypes()
+        {
+            return identifierTypes;
+        }
+
         public bool TryResolveCustomType(string name, [NotNullWhen(true)] out NubType? customType)
         {
             customType = customTypes.GetValueOrDefault(name);
@@ -61,7 +66,7 @@ public class ModuleGraph(Dictionary<string, ModuleGraph.Module> modules)
             asts.Add(ast);
         }
 
-        public ModuleGraph Build(out List<Diagnostic> diagnostics)
+        public ModuleGraph? Build(out List<Diagnostic> diagnostics)
         {
             diagnostics = [];
 
@@ -71,24 +76,11 @@ public class ModuleGraph(Dictionary<string, ModuleGraph.Module> modules)
             // First pass: Register modules
             foreach (var ast in asts)
             {
-                var moduleDefinitions = ast.Definitions.OfType<NodeDefinitionModule>().ToList();
-
-                if (moduleDefinitions.Count == 0)
-                    diagnostics.Add(Diagnostic.Error("Missing module declaration").At(ast.FileName, 1, 1, 1).Build());
-
-                foreach (var extraModuleDefinition in moduleDefinitions.Skip(1))
-                    diagnostics.Add(Diagnostic.Warning("Duplicate module declaration will be ignored").At(ast.FileName, extraModuleDefinition).Build());
-
-                if (moduleDefinitions.Count >= 1)
+                if (!modules.ContainsKey(ast.ModuleName.Ident))
                 {
-                    var currentModule = moduleDefinitions[0].Name.Ident;
-
-                    if (!modules.ContainsKey(currentModule))
-                    {
-                        var module = new Module(currentModule);
-                        modules.Add(currentModule, module);
-                        astModuleCache[ast] = module;
-                    }
+                    var module = new Module(ast.ModuleName.Ident);
+                    modules.Add(ast.ModuleName.Ident, module);
+                    astModuleCache[ast] = module;
                 }
             }
 
@@ -133,6 +125,9 @@ public class ModuleGraph(Dictionary<string, ModuleGraph.Module> modules)
                 }
             }
 
+            if (diagnostics.Any(x => x.Severity == DiagnosticSeverity.Error))
+                return null;
+
             return new ModuleGraph(modules);
 
             NubType ResolveType(NodeType node)
diff --git a/compiler/NubType.cs b/compiler/NubType.cs
index 6a77525..3223327 100644
--- a/compiler/NubType.cs
+++ b/compiler/NubType.cs
@@ -1,3 +1,5 @@
+using System.Text;
+
 namespace Compiler;
 
 public abstract class NubType
@@ -153,6 +155,8 @@ public sealed class NubTypeFunc : NubType
     public IReadOnlyList<NubType> Parameters { get; }
     public NubType ReturnType { get; }
 
+    public string MangledName(string name, string module) => SymbolNameGen.Exported(name, module, this);
+
     private NubTypeFunc(List<NubType> parameters, NubType returnType)
     {
         Parameters = parameters;
@@ -162,4 +166,110 @@ public sealed class NubTypeFunc : NubType
     public override string ToString() => $"func({string.Join(' ', Parameters)}): {ReturnType}";
 
     private readonly record struct Signature(IReadOnlyList<NubType> Parameters, NubType ReturnType);
-}
\ No newline at end of file
+}
+
+static class TypeMangler
+{
+    public static string Encode(NubType type)
+    {
+        var sb = new StringBuilder();
+        Encode(type, sb);
+        return sb.ToString();
+    }
+
+    private static void Encode(NubType type, StringBuilder sb)
+    {
+        switch (type)
+        {
+            case NubTypeVoid:
+                sb.Append('V');
+                break;
+
+            case NubTypeBool:
+                sb.Append('B');
+                break;
+
+            case NubTypeUInt u:
+                sb.Append("U(");
+                sb.Append(u.Width);
+                sb.Append(')');
+                break;
+
+            case NubTypeSInt s:
+                sb.Append("U(");
+                sb.Append(s.Width);
+                sb.Append(')');
+                break;
+
+            case NubTypeString:
+                sb.Append('S');
+                break;
+
+            case NubTypePointer p:
+                sb.Append("P(");
+                Encode(p.To, sb);
+                sb.Append(')');
+                break;
+
+            case NubTypeStruct st:
+                sb.Append($"T({st.Module}::{st.Name})").Append(st.Module).Append("::").Append(st.Name).Append(')');
+                break;
+
+            case NubTypeFunc fn:
+                sb.Append("F(");
+                for (int i = 0; i < fn.Parameters.Count; i++)
+                {
+                    Encode(fn.Parameters[i], sb);
+                    sb.Append(',');
+                }
+                Encode(fn.ReturnType, sb);
+                sb.Append(')');
+                break;
+
+            default:
+                throw new NotSupportedException(type.GetType().Name);
+        }
+    }
+}
+
+static class Hashing
+{
+    public static ulong Fnv1a64(string text)
+    {
+        const ulong offset = 14695981039346656037UL;
+        const ulong prime  = 1099511628211UL;
+
+        ulong hash = offset;
+        foreach (var c in Encoding.UTF8.GetBytes(text))
+        {
+            hash ^= c;
+            hash *= prime;
+        }
+
+        return hash;
+    }
+}
+
+static class SymbolNameGen
+{
+    public static string Exported(string module, string function, NubType type)
+    {
+        var canonical = TypeMangler.Encode(type);
+        var hash = Hashing.Fnv1a64(canonical);
+
+        return $"nub_{Sanitize(module)}_{Sanitize(function)}_{hash:x16}";
+    }
+
+    private static string Sanitize(string s)
+    {
+        var sb = new StringBuilder(s.Length);
+        foreach (var c in s)
+        {
+            if (char.IsLetterOrDigit(c))
+                sb.Append(c);
+            else
+                sb.Append('_');
+        }
+        return sb.ToString();
+    }
+}
diff --git a/compiler/Parser.cs b/compiler/Parser.cs
index 1d9fe6d..02e586d 100644
--- a/compiler/Parser.cs
+++ b/compiler/Parser.cs
@@ -4,20 +4,25 @@ namespace Compiler;
 
 public sealed class Parser(string fileName, List<Token> tokens)
 {
-    public static Ast Parse(string fileName, List<Token> tokens, out List<Diagnostic> diagnostics)
+    public static Ast? Parse(string fileName, List<Token> tokens, out List<Diagnostic> diagnostics)
     {
         return new Parser(fileName, tokens).Parse(out diagnostics);
     }
 
     private int index;
 
-    private Ast Parse(out List<Diagnostic> diagnostics)
+    private Ast? Parse(out List<Diagnostic> diagnostics)
     {
         var definitions = new List<NodeDefinition>();
         diagnostics = [];
 
+        TokenIdent? moduleName = null;
+
         try
         {
+            ExpectKeyword(Keyword.Module);
+            moduleName = ExpectIdent();
+
             while (Peek() != null)
             {
                 definitions.Add(ParseDefinition());
@@ -28,7 +33,10 @@ public sealed class Parser(string fileName, List<Token> tokens)
             diagnostics.Add(e.Diagnostic);
         }
 
-        return new Ast(definitions, fileName);
+        if (moduleName == null || diagnostics.Any(x => x.Severity == DiagnosticSeverity.Error))
+            return null;
+
+        return new Ast(fileName, moduleName, definitions);
     }
 
     private NodeDefinition ParseDefinition()
@@ -76,12 +84,6 @@ public sealed class Parser(string fileName, List<Token> tokens)
             return new NodeDefinitionStruct(TokensFrom(startIndex), name, fields);
         }
 
-        if (TryExpectKeyword(Keyword.Module))
-        {
-            var name = ExpectIdent();
-            return new NodeDefinitionModule(TokensFrom(startIndex), name);
-        }
-
         throw new CompileException(Diagnostic.Error("Not a valid definition").At(fileName, Peek()).Build());
     }
 
@@ -355,6 +357,17 @@ public sealed class Parser(string fileName, List<Token> tokens)
         return tokens.GetRange(startIndex, index - startIndex);
     }
 
+    private void ExpectKeyword(Keyword keyword)
+    {
+        if (Peek() is TokenKeyword token && token.Keyword == keyword)
+        {
+            Next();
+            return;
+        }
+
+        throw new CompileException(Diagnostic.Error($"Expected '{keyword.AsString()}'").At(fileName, Peek()).Build());
+    }
+
     private bool TryExpectKeyword(Keyword keyword)
     {
         if (Peek() is TokenKeyword token && token.Keyword == keyword)
@@ -529,9 +542,10 @@ public sealed class Parser(string fileName, List<Token> tokens)
     }
 }
 
-public sealed class Ast(List<NodeDefinition> definitions, string fileName)
+public sealed class Ast(string fileName, TokenIdent moduleName, List<NodeDefinition> definitions)
 {
     public string FileName { get; } = fileName;
+    public TokenIdent ModuleName { get; } = moduleName;
     public List<NodeDefinition> Definitions { get; } = definitions;
 }
 
@@ -542,11 +556,6 @@ public abstract class Node(List<Token> tokens)
 
 public abstract class NodeDefinition(List<Token> tokens) : Node(tokens);
 
-public sealed class NodeDefinitionModule(List<Token> tokens, TokenIdent name) : NodeDefinition(tokens)
-{
-    public TokenIdent Name { get; } = name;
-}
-
 public sealed class NodeDefinitionFunc(List<Token> tokens, TokenIdent name, List<NodeDefinitionFunc.Param> parameters, NodeStatement body, NodeType returnType) : NodeDefinition(tokens)
 {
     public TokenIdent Name { get; } = name;
diff --git a/compiler/Program.cs b/compiler/Program.cs
index a7c3008..bb74939 100644
--- a/compiler/Program.cs
+++ b/compiler/Program.cs
@@ -13,7 +13,7 @@ foreach (var fileName in args)
     foreach (var diagnostic in tokenizerDiagnostics)
         DiagnosticFormatter.Print(diagnostic, Console.Error);
 
-    if (tokenizerDiagnostics.Any(x => x.Severity == DiagnosticSeverity.Error))
+    if (tokens == null)
         return 1;
 
     var ast = Parser.Parse(fileName, tokens, out var parserDiagnostics);
@@ -21,7 +21,7 @@ foreach (var fileName in args)
     foreach (var diagnostic in parserDiagnostics)
         DiagnosticFormatter.Print(diagnostic, Console.Error);
 
-    if (parserDiagnostics.Any(x => x.Severity == DiagnosticSeverity.Error))
+    if (ast == null)
         return 1;
 
     moduleGraphBuilder.AddAst(ast);
@@ -33,7 +33,7 @@ var moduleGraph = moduleGraphBuilder.Build(out var moduleGraphDiagnostics);
 foreach (var diagnostic in moduleGraphDiagnostics)
     DiagnosticFormatter.Print(diagnostic, Console.Error);
 
-if (moduleGraphDiagnostics.Any(x => x.Severity == DiagnosticSeverity.Error))
+if (moduleGraph == null)
     return 1;
 
 var functions = new List<TypedNodeDefinitionFunc>();
@@ -42,7 +42,7 @@ foreach (var ast in asts)
 {
     foreach (var func in ast.Definitions.OfType<NodeDefinitionFunc>())
     {
-        var typedFunction = TypeChecker.CheckFunction(ast.FileName, func, moduleGraph, out var typeCheckerDiagnostics);
+        var typedFunction = TypeChecker.CheckFunction(ast.FileName, ast.ModuleName.Ident, func, moduleGraph, out var typeCheckerDiagnostics);
 
         foreach (var diagnostic in typeCheckerDiagnostics)
             DiagnosticFormatter.Print(diagnostic, Console.Error);
@@ -61,6 +61,6 @@ Directory.CreateDirectory(".build");
 
 File.WriteAllText(".build/out.c", output);
 
-Process.Start("gcc", ["-Og", "-g", "-o", ".build/out", ".build/out.c"]);
+Process.Start("gcc", ["-Og", "-g", "-o", ".build/out", ".build/out.c", "-fvisibility=hidden","-fno-builtin"]);
 
 return 0;
\ No newline at end of file
diff --git a/compiler/Tokenizer.cs b/compiler/Tokenizer.cs
index d057834..f4b2014 100644
--- a/compiler/Tokenizer.cs
+++ b/compiler/Tokenizer.cs
@@ -5,7 +5,7 @@ namespace Compiler;
 
 public sealed class Tokenizer(string fileName, string contents)
 {
-    public static List<Token> Tokenize(string fileName, string contents, out List<Diagnostic> diagnostics)
+    public static List<Token>? Tokenize(string fileName, string contents, out List<Diagnostic> diagnostics)
     {
         return new Tokenizer(fileName, contents).Tokenize(out diagnostics);
     }
@@ -14,7 +14,7 @@ public sealed class Tokenizer(string fileName, string contents)
     private int line = 1;
     private int column = 1;
 
-    private List<Token> Tokenize(out List<Diagnostic> diagnostics)
+    private List<Token>? Tokenize(out List<Diagnostic> diagnostics)
     {
         var tokens = new List<Token>();
         diagnostics = [];
@@ -53,6 +53,9 @@ public sealed class Tokenizer(string fileName, string contents)
             }
         }
 
+        if (diagnostics.Any(x => x.Severity == DiagnosticSeverity.Error))
+            return null;
+
         return tokens;
     }
 
diff --git a/compiler/TypeChecker.cs b/compiler/TypeChecker.cs
index 27f835e..8a2838d 100644
--- a/compiler/TypeChecker.cs
+++ b/compiler/TypeChecker.cs
@@ -1,10 +1,10 @@
 namespace Compiler;
 
-public sealed class TypeChecker(string fileName, NodeDefinitionFunc function, ModuleGraph moduleGraph)
+public sealed class TypeChecker(string fileName, string moduleName, NodeDefinitionFunc function, ModuleGraph moduleGraph)
 {
-    public static TypedNodeDefinitionFunc? CheckFunction(string fileName, NodeDefinitionFunc function, ModuleGraph moduleGraph, out List<Diagnostic> diagnostics)
+    public static TypedNodeDefinitionFunc? CheckFunction(string fileName, string moduleName, NodeDefinitionFunc function, ModuleGraph moduleGraph, out List<Diagnostic> diagnostics)
     {
-        return new TypeChecker(fileName, function, moduleGraph).CheckFunction(out diagnostics);
+        return new TypeChecker(fileName, moduleName, function, moduleGraph).CheckFunction(out diagnostics);
     }
 
     private readonly Scope scope = new(null);
@@ -52,7 +52,7 @@ public sealed class TypeChecker(string fileName, NodeDefinitionFunc function, Mo
         if (body == null || returnType == null || invalidParameter)
             return null;
 
-        return new TypedNodeDefinitionFunc(function.Tokens, function.Name, parameters, body, returnType);
+        return new TypedNodeDefinitionFunc(function.Tokens, moduleName, function.Name, parameters, body, returnType);
     }
 
     private TypedNodeDefinitionFunc.Param CheckDefinitionFuncParameter(NodeDefinitionFunc.Param node)
@@ -409,15 +409,28 @@ public abstract class TypedNode(List<Token> tokens)
     public List<Token> Tokens { get; } = tokens;
 }
 
-public abstract class TypedNodeDefinition(List<Token> tokens) : TypedNode(tokens);
+public abstract class TypedNodeDefinition(List<Token> tokens, string module) : TypedNode(tokens)
+{
+    public string Module { get; } = module;
+}
 
-public sealed class TypedNodeDefinitionFunc(List<Token> tokens, TokenIdent name, List<TypedNodeDefinitionFunc.Param> parameters, TypedNodeStatement body, NubType returnType) : TypedNodeDefinition(tokens)
+public sealed class TypedNodeDefinitionFunc(List<Token> tokens, string module, TokenIdent name, List<TypedNodeDefinitionFunc.Param> parameters, TypedNodeStatement body, NubType returnType) : TypedNodeDefinition(tokens, module)
 {
     public TokenIdent Name { get; } = name;
     public List<Param> Parameters { get; } = parameters;
     public TypedNodeStatement Body { get; } = body;
     public NubType ReturnType { get; } = returnType;
 
+    public NubTypeFunc GetNubType()
+    {
+        return NubTypeFunc.Get(Parameters.Select(x => x.Type).ToList(), ReturnType);
+    }
+
+    public string GetMangledName()
+    {
+        return SymbolNameGen.Exported(Module, Name.Ident, GetNubType());
+    }
+
     public sealed class Param(List<Token> tokens, TokenIdent name, NubType type) : TypedNode(tokens)
     {
         public TokenIdent Name { get; } = name;