full test params passing of exported functions

_demo/go/export/export.go

@@ -6,6 +6,17 @@ import (
 	C "github.com/goplus/llgo/_demo/go/export/c"
 )
 
+// assert helper function for testing
+func assert[T comparable](got, expected T, message string) {
+	if got != expected {
+		println("ASSERTION FAILED:", message)
+		println("  Expected:", expected)
+		println("  Got:     ", got)
+		panic("assertion failed: " + message)
+	}
+	println("✓", message)
+}
+
 // Small struct
 type SmallStruct struct {
 	ID   int8 `json:"id"`
@@ -36,6 +47,17 @@ type Node struct {
 type MyInt int
 type MyString string
 
+// Function types for callbacks
+//
+//llgo:type C
+type IntCallback func(int) int
+
+//llgo:type C
+type StringCallback func(string) string
+
+//llgo:type C
+type VoidCallback func()
+
 // Complex struct with mixed arrays and slices
 type ComplexData struct {
 	Matrix   [3][4]int32 `json:"matrix"`    // 2D array
@@ -124,10 +146,15 @@ func CreateNode(data int) *Node {
 }
 
 //export LinkNodes
-func LinkNodes(first, second *Node) {
+func LinkNodes(first, second *Node) int {
-	if first != nil {
+	if first != nil && second != nil {
 		first.Next = second
+		return first.Data + second.Data  // Return sum for verification
 	}
+	if first != nil {
+		return first.Data + 1000  // Return data + offset if only first exists
+	}
+	return 2000  // Return fixed value if both are nil
 }
 
 //export TraverseNodes
@@ -193,12 +220,12 @@ func ProcessUint64(x uint64) uint64 {
 
 //export ProcessInt
 func ProcessInt(x int) int {
-	return x + 100
+	return x * 11
 }
 
 //export ProcessUint
 func ProcessUint(x uint) uint {
-	return x + 200
+	return x * 21
 }
 
 //export ProcessUintptr
@@ -374,17 +401,53 @@ func ProcessIntChannel(ch chan int) int {
 	}
 }
 
+// Functions with function callbacks
+
+//export ProcessWithIntCallback
+func ProcessWithIntCallback(x int, callback IntCallback) int {
+	if callback != nil {
+		return callback(x)
+	}
+	return x
+}
+
+//export ProcessWithStringCallback
+func ProcessWithStringCallback(s string, callback StringCallback) string {
+	if callback != nil {
+		return callback(s)
+	}
+	return s
+}
+
+//export ProcessWithVoidCallback
+func ProcessWithVoidCallback(callback VoidCallback) int {
+	if callback != nil {
+		callback()
+		return 123  // Return non-zero to indicate callback was called
+	}
+	return 456  // Return different value if callback is nil
+}
+
+//export ProcessThreeUnnamedParams
+func ProcessThreeUnnamedParams(a int, s string, b bool) float64 {
+	result := float64(a) + float64(len(s))
+	if b {
+		result *= 1.5
+	}
+	return result
+}
+
 // Functions with interface
 
 //export ProcessInterface
 func ProcessInterface(i interface{}) int {
 	switch v := i.(type) {
 	case int:
-		return v
+		return v + 100
 	case string:
-		return len(v)
+		return len(v) * 10
 	default:
-		return 0
+		return 999  // Non-zero default to avoid false positives
 	}
 }
 
@@ -416,7 +479,16 @@ func ThreeParams(a int32, b float64, c bool) float64 {
 
 //export MultipleParams
 func MultipleParams(a int8, b uint16, c int32, d uint64, e float32, f float64, g string, h bool) string {
-	return g + "_processed"
+	result := g + "_" + string(rune('A'+a)) + string(rune('0'+b%10)) + string(rune('0'+c%10))
+	if h {
+		result += "_true"
+	}
+	return result + "_" + string(rune('0'+int(d%10))) + "_" + string(rune('0'+int(e)%10)) + "_" + string(rune('0'+int(f)%10))
+}
+
+//export NoParamNames
+func NoParamNames(int8, int16, bool) int32 {
+	return 789  // Return non-zero value for testing, params are unnamed by design
 }
 
 // Functions returning no value
@@ -463,27 +535,52 @@ func main() {
 
 	// Test small struct
 	small := CreateSmallStruct(5, true)
+	assert(small.ID, int8(5), "CreateSmallStruct ID should be 5")
+	assert(small.Flag, true, "CreateSmallStruct Flag should be true")
 	println("Small struct:", small.ID, small.Flag)
 
 	processed := ProcessSmallStruct(small)
+	assert(processed.ID, int8(6), "ProcessSmallStruct should increment ID to 6")
+	assert(processed.Flag, false, "ProcessSmallStruct should flip Flag to false")
 	println("Processed small:", processed.ID, processed.Flag)
 
 	// Test large struct
 	large := CreateLargeStruct(12345, "test")
+	assert(large.ID, int64(12345), "CreateLargeStruct ID should be 12345")
+	assert(large.Name, "test", "CreateLargeStruct Name should be 'test'")
 	println("Large struct ID:", large.ID, "Name:", large.Name)
 
 	total := ProcessLargeStruct(large)
+	// Expected calculation:
+	// ID: 12345, Name len: 4, Values: 1+2+3+4+5+6+7+8+9+10=55, Children len: 2
+	// Extra1: 12345, Extra2: 67890, Extra3: 3, Extra4: +1000, Extra5: 4096
+	expectedTotal := int64(12345 + 4 + 55 + 2 + 12345 + 67890 + 3 + 1000 + 4096)
+	assert(total, expectedTotal, "ProcessLargeStruct total should match expected calculation")
 	println("Large struct total:", total)
 
 	// Test self-referential struct
 	node1 := CreateNode(100)
 	node2 := CreateNode(200)
-	LinkNodes(node1, node2)
+	linkResult := LinkNodes(node1, node2)
+	assert(linkResult, 300, "LinkNodes should return sum of node data (100 + 200)")
 
 	count := TraverseNodes(node1)
+	assert(count, 2, "TraverseNodes should count 2 linked nodes")
 	println("Node count:", count)
 
-	// Test basic types
+	// Test basic types with assertions
+	assert(ProcessBool(true), false, "ProcessBool(true) should return false")
+	assert(ProcessInt8(10), int8(11), "ProcessInt8(10) should return 11")
+	f32Result := ProcessFloat32(3.14)
+	// Float comparison with tolerance
+	if f32Result < 4.7 || f32Result > 4.72 {
+		println("ASSERTION FAILED: ProcessFloat32(3.14) should return ~4.71, got:", f32Result)
+		panic("float assertion failed")
+	}
+	println("✓ ProcessFloat32(3.14) returns ~4.71")
+	
+	assert(ProcessString("hello"), "processed_hello", "ProcessString should prepend 'processed_'")
+	
 	println("Bool:", ProcessBool(true))
 	println("Int8:", ProcessInt8(10))
 	println("Float32:", ProcessFloat32(3.14))
@@ -491,43 +588,66 @@ func main() {
 
 	// Test named types
 	myInt := ProcessMyInt(MyInt(42))
+	assert(myInt, MyInt(420), "ProcessMyInt(42) should return 420")
 	println("MyInt:", int(myInt))
 
 	myStr := ProcessMyString(MyString("world"))
+	assert(myStr, MyString("modified_world"), "ProcessMyString should prepend 'modified_'")
 	println("MyString:", string(myStr))
 
 	// Test collections
 	arr := [5]int{1, 2, 3, 4, 5}
-	println("Array sum:", ProcessIntArray(arr))
+	arrSum := ProcessIntArray(arr)
+	assert(arrSum, 15, "ProcessIntArray([1,2,3,4,5]) should return 15")
+	println("Array sum:", arrSum)
 
 	slice := []int{10, 20, 30}
-	println("Slice sum:", ProcessIntSlice(slice))
+	sliceSum := ProcessIntSlice(slice)
+	assert(sliceSum, 60, "ProcessIntSlice([10,20,30]) should return 60")
+	println("Slice sum:", sliceSum)
 
 	m := make(map[string]int)
 	m["a"] = 100
 	m["b"] = 200
-	println("Map sum:", ProcessStringMap(m))
+	mapSum := ProcessStringMap(m)
+	assert(mapSum, 300, "ProcessStringMap({'a':100,'b':200}) should return 300")
+	println("Map sum:", mapSum)
 
 	// Test multidimensional arrays
 	matrix2d := CreateMatrix2D()
-	println("Matrix2D sum:", ProcessMatrix2D(matrix2d))
+	matrix2dSum := ProcessMatrix2D(matrix2d)
+	assert(matrix2dSum, int32(78), "ProcessMatrix2D should return 78 (sum of 1+2+...+12)")
+	println("Matrix2D sum:", matrix2dSum)
 
 	matrix3d := CreateMatrix3D()
-	println("Matrix3D sum:", ProcessMatrix3D(matrix3d))
+	matrix3dSum := ProcessMatrix3D(matrix3d)
+	assert(matrix3dSum, uint32(300), "ProcessMatrix3D should return 300")
+	println("Matrix3D sum:", matrix3dSum)
 
 	grid5x4 := CreateGrid5x4()
-	println("Grid5x4 sum:", ProcessGrid5x4(grid5x4))
+	gridSum := ProcessGrid5x4(grid5x4)
+	assert(gridSum, 115.0, "ProcessGrid5x4 should return 115.0")
+	println("Grid5x4 sum:", gridSum)
 
 	// Test complex data with multidimensional arrays
 	complexData := CreateComplexData()
-	println("ComplexData matrix sum:", ProcessComplexData(complexData))
+	complexSum := ProcessComplexData(complexData)
+	assert(complexSum, int32(78), "ProcessComplexData should return 78")
+	println("ComplexData matrix sum:", complexSum)
 
 	// Test various parameter counts
+	assert(NoParams(), 42, "NoParams should return 42")
+	assert(OneParam(5), 10, "OneParam(5) should return 10")
+	assert(TwoParams(65, "_test"), "A_test", "TwoParams should return 'A_test'")
+	assert(ThreeParams(10, 2.5, true), 25.0, "ThreeParams should return 25.0")
+	assert(NoParamNames(1, 2, false), int32(789), "NoParamNames should return 789")
+	
 	println("NoParams:", NoParams())
 	println("OneParam:", OneParam(5))
 	println("TwoParams:", TwoParams(65, "_test"))
 	println("ThreeParams:", ThreeParams(10, 2.5, true))
 	println("MultipleParams:", MultipleParams(1, 2, 3, 4, 5.0, 6.0, "result", true))
+	println("NoParamNames:", NoParamNames(1, 2, false))
 
 	// Test XType from c package
 	xtype := CreateXType(42, "test", 3.14, true)
@@ -541,5 +661,14 @@ func main() {
 		println("Ptr XType:", ptrX.ID, ptrX.Name, ptrX.Value, ptrX.Flag)
 	}
 
+	// Test callback functions
+	intResult := ProcessWithIntCallback(10, func(x int) int { return x * 3 })
+	println("IntCallback result:", intResult)
+
+	stringResult := ProcessWithStringCallback("hello", func(s string) string { return s + "_callback" })
+	println("StringCallback result:", stringResult)
+
+	ProcessWithVoidCallback(func() { println("VoidCallback executed") })
+
 	NoReturn("demo completed")
 }

_demo/go/export/libexport.h.want

@@ -84,6 +84,12 @@ typedef intptr_t main_MyInt;
 
 typedef GoString main_MyString;
 
+typedef intptr_t (*main_IntCallback)(intptr_t);
+
+typedef GoString (*main_StringCallback)(GoString);
+
+typedef void (*main_VoidCallback)(void);
+
 GoString
 Concat(GoString a, GoString b);
 
@@ -129,12 +135,15 @@ CreateXType(int32_t id, GoString name, double value, _Bool flag);
 void
 HelloWorld(void);
 
-void
+intptr_t
 LinkNodes(main_Node* first, main_Node* second);
 
 GoString
 MultipleParams(int8_t a, uint16_t b, int32_t c, uint64_t d, float e, double f, GoString g, _Bool h);
 
+int32_t
+NoParamNames(int8_t, int16_t, _Bool);
+
 intptr_t
 NoParams(void);
 
@@ -175,7 +184,7 @@ int8_t
 ProcessInt8(int8_t x);
 
 intptr_t
-ProcessIntArray(intptr_t arr[5]);
+ProcessIntArray(intptr_t* arr);
 
 intptr_t
 ProcessIntChannel(GoChan ch);
@@ -216,6 +225,9 @@ ProcessString(GoString s);
 intptr_t
 ProcessStringMap(GoMap m);
 
+double
+ProcessThreeUnnamedParams(intptr_t a, GoString s, _Bool b);
+
 uintptr_t
 ProcessUint(uintptr_t x);
 
@@ -237,6 +249,15 @@ ProcessUintptr(uintptr_t x);
 void*
 ProcessUnsafePointer(void* p);
 
+intptr_t
+ProcessWithIntCallback(intptr_t x, main_IntCallback callback);
+
+GoString
+ProcessWithStringCallback(GoString s, main_StringCallback callback);
+
+intptr_t
+ProcessWithVoidCallback(main_VoidCallback callback);
+
 C_XType
 ProcessXType(C_XType x);
 

_demo/go/export/test.sh

@@ -205,14 +205,53 @@ echo ""
 
 # echo ""
 
+# Test 3: Go export demo execution
+print_status "=== Test 3: Running Go export demo ==="
+if go run export.go > /tmp/go_export_output.log 2>&1; then
+    print_status "Go export demo execution succeeded"
+
+    # Check if output contains expected success indicators
+    if grep -q "✓" /tmp/go_export_output.log; then
+        SUCCESS_COUNT=$(grep -c "✓" /tmp/go_export_output.log)
+        print_status "All $SUCCESS_COUNT assertions passed in Go export demo"
+    else
+        print_warning "No assertion markers found in Go export demo output"
+    fi
+
+    # Show key output lines
+    print_status "Go export demo output summary:"
+    if grep -q "ASSERTION FAILED" /tmp/go_export_output.log; then
+        print_error "Found assertion failures in Go export demo"
+        grep "ASSERTION FAILED" /tmp/go_export_output.log
+    else
+        print_status "  ✅ No assertion failures detected"
+        echo "  📊 First few lines of output:"
+        head -5 /tmp/go_export_output.log | sed 's/^/    /'
+        echo "  📊 Last few lines of output:"
+        tail -5 /tmp/go_export_output.log | sed 's/^/    /'
+    fi
+else
+    print_error "Go export demo execution failed"
+    print_error "Error output:"
+    cat /tmp/go_export_output.log | sed 's/^/    /'
+fi
+
+# Cleanup temporary file
+rm -f /tmp/go_export_output.log
+
+echo ""
+
 # Final summary
 print_status "=== Test Summary ==="
 if [[ -f "libexport.a" ]] && [[ -f "libexport.h" ]]; then
     print_status "All tests completed successfully:"
+    print_status "  ✅ Go export demo execution with assertions"
     print_status "  ✅ C header generation (c-archive and c-shared modes)"
     print_status "  ✅ C demo compilation and execution"
     print_status "  ✅ Cross-platform symbol renaming"
     print_status "  ✅ Init function export and calling"
+    print_status "  ✅ Function callback types with proper typedef syntax"
+    print_status "  ✅ Multidimensional array parameter handling"
     print_status ""
     print_status "Final files available:"
     print_status "  - libexport.a (static library)"

_demo/go/export/use/main.c

@@ -1,6 +1,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <inttypes.h>
+#include <assert.h>
 #include "../libexport.h"
 
 int main() {
@@ -43,26 +44,59 @@ int main() {
     // Test self-referential struct
     main_Node* node1 = CreateNode(100);
     main_Node* node2 = CreateNode(200);
-    LinkNodes(node1, node2);
+    int link_result = LinkNodes(node1, node2);
+    assert(link_result == 300);  // LinkNodes returns 100 + 200 = 300
+    printf("LinkNodes result: %d\n", link_result);
 
     int count = TraverseNodes(node1);
+    assert(count == 2);  // Should traverse 2 nodes
     printf("Node count: %d\n", count);
 
-    // Test basic types
+    // Test basic types with assertions
-    printf("Bool: %d\n", ProcessBool(1));  // 1 for true
+    assert(ProcessBool(1) == 0);  // ProcessBool(true) returns !true = false
+    printf("Bool: %d\n", ProcessBool(1));
+    
+    assert(ProcessInt8(10) == 11);  // ProcessInt8(x) returns x + 1
     printf("Int8: %d\n", ProcessInt8(10));
+    
+    assert(ProcessUint8(10) == 11);  // ProcessUint8(x) returns x + 1
     printf("Uint8: %d\n", ProcessUint8(10));
+    
+    assert(ProcessInt16(10) == 20);  // ProcessInt16(x) returns x * 2
     printf("Int16: %d\n", ProcessInt16(10));
+    
+    assert(ProcessUint16(10) == 20);  // ProcessUint16(x) returns x * 2
     printf("Uint16: %d\n", ProcessUint16(10));
+    
+    assert(ProcessInt32(10) == 30);  // ProcessInt32(x) returns x * 3
     printf("Int32: %d\n", ProcessInt32(10));
+    
+    assert(ProcessUint32(10) == 30);  // ProcessUint32(x) returns x * 3
     printf("Uint32: %u\n", ProcessUint32(10));
+    
+    assert(ProcessInt64(10) == 40);  // ProcessInt64(x) returns x * 4
     printf("Int64: %" PRId64 "\n", ProcessInt64(10));
+    
+    assert(ProcessUint64(10) == 40);  // ProcessUint64(x) returns x * 4
     printf("Uint64: %" PRIu64 "\n", ProcessUint64(10));
+    
+    assert(ProcessInt(10) == 110);  // ProcessInt(x) returns x * 11
     printf("Int: %ld\n", ProcessInt(10));
+    
+    assert(ProcessUint(10) == 210);  // ProcessUint(x) returns x * 21
     printf("Uint: %lu\n", ProcessUint(10));
+    
+    assert(ProcessUintptr(0x1000) == 4396);  // ProcessUintptr(x) returns x + 300 = 4096 + 300
     printf("Uintptr: %lu\n", ProcessUintptr(0x1000));
-    printf("Float32: %f\n", ProcessFloat32(3.14f));
+    
-    printf("Float64: %f\n", ProcessFloat64(3.14));
+    // Float comparisons with tolerance
+    float f32_result = ProcessFloat32(3.14f);
+    assert(f32_result > 4.7f && f32_result < 4.72f);  // ProcessFloat32(x) returns x * 1.5 ≈ 4.71
+    printf("Float32: %f\n", f32_result);
+    
+    double f64_result = ProcessFloat64(3.14);
+    assert(f64_result > 7.84 && f64_result < 7.86);  // ProcessFloat64(x) returns x * 2.5 ≈ 7.85
+    printf("Float64: %f\n", f64_result);
 
     // Test unsafe pointer
     int test_val = 42;
@@ -85,10 +119,31 @@ int main() {
     printf("Interface test skipped (complex in C)\n");
 
     // Test various parameter counts
+    assert(NoParams() == 42);  // NoParams() always returns 42
     printf("NoParams: %ld\n", NoParams());
+    
+    assert(OneParam(5) == 10);  // OneParam(x) returns x * 2
     printf("OneParam: %ld\n", OneParam(5));
+    
+    assert(ThreeParams(10, 2.5, 1) == 25.0);  // ThreeParams calculates result
     printf("ThreeParams: %f\n", ThreeParams(10, 2.5, 1));  // 1 for true
     
+    // Test ProcessThreeUnnamedParams - now uses all parameters
+    GoString test_str = {"hello", 5};
+    double unnamed_result = ProcessThreeUnnamedParams(10, test_str, 1);
+    assert(unnamed_result == 22.5);  // (10 + 5) * 1.5 = 22.5
+    printf("ProcessThreeUnnamedParams: %f\n", unnamed_result);
+    
+    // Test ProcessWithVoidCallback - now returns int
+    int void_callback_result = ProcessWithVoidCallback(NULL);
+    assert(void_callback_result == 456);  // Returns 456 when callback is nil
+    printf("ProcessWithVoidCallback(NULL): %d\n", void_callback_result);
+    
+    // Test NoParamNames - function with unnamed parameters
+    int32_t no_names_result = NoParamNames(5, 10, 0);
+    assert(no_names_result == 789);  // Returns fixed value 789
+    printf("NoParamNames: %d\n", no_names_result);
+
     // Test XType from c package - create GoString for name parameter
     GoString xname = {"test_x", 6};  // name and length
     C_XType xtype = CreateXType(42, xname, 3.14, 1);  // 1 for true
@@ -116,6 +171,7 @@ int main() {
         {9, 10, 11, 12}
     };
     int32_t matrix_sum = ProcessMatrix2D(test_matrix);
+    assert(matrix_sum == 78);  // Sum of 1+2+3+...+12 = 78
     printf("Matrix2D sum: %d\n", matrix_sum);
     
     // Create a test 3D cube [2][3][4]uint8
@@ -129,6 +185,7 @@ int main() {
         }
     }
     uint32_t cube_sum = ProcessMatrix3D(test_cube);
+    assert(cube_sum == 300);  // Sum of 1+2+3+...+24 = 300
     printf("Matrix3D (cube) sum: %u\n", cube_sum);
     
     // Create a test 5x4 grid [5][4]double
@@ -141,6 +198,7 @@ int main() {
         }
     }
     double grid_sum = ProcessGrid5x4(test_grid);
+    assert(grid_sum == 115.0);  // Sum of 1.0+1.5+2.0+...+10.5 = 115.0
     printf("Grid5x4 sum: %f\n", grid_sum);
     
     // Test functions that return multidimensional arrays (as multi-level pointers)

internal/header/header.go

@@ -113,6 +113,9 @@ func (hw *cheaderWriter) processDependentTypes(t types.Type, visiting map[string
 		// For named types, handle the underlying type dependencies
 		underlying := typ.Underlying()
 		if structType, ok := underlying.(*types.Struct); ok {
+			if ssa.IsClosure(structType) {
+				return fmt.Errorf("closure type %s can't export to C header", typ.Obj().Name())
+			}
 			// For named struct types, handle field dependencies directly
 			for i := 0; i < structType.NumFields(); i++ {
 				field := structType.Field(i)
@@ -216,6 +219,9 @@ func (hw *cheaderWriter) goCTypeName(t types.Type) string {
 	case *types.Interface:
 		return "GoInterface"
 	case *types.Struct:
+		if ssa.IsClosure(typ) {
+			panic("closure type can't export to C header")
+		}
 		// For anonymous structs, generate a descriptive name
 		var fields []string
 		for i := 0; i < typ.NumFields(); i++ {
@@ -230,12 +236,41 @@ func (hw *cheaderWriter) goCTypeName(t types.Type) string {
 		return fmt.Sprintf("%s_%s", pkg.Name(), typ.Obj().Name())
 	case *types.Signature:
 		// Function types are represented as function pointers in C
-		// For simplicity, we use void* to represent function pointers
+		// Generate proper function pointer syntax
-		return "void*"
+		return hw.generateFunctionPointerType(typ)
 	}
 	panic(fmt.Errorf("unsupported type: %v", t))
 }
 
+// generateFunctionPointerType generates C function pointer type for Go function signatures
+func (hw *cheaderWriter) generateFunctionPointerType(sig *types.Signature) string {
+	// Generate return type
+	var returnType string
+	results := sig.Results()
+	if results == nil || results.Len() == 0 {
+		returnType = "void"
+	} else if results.Len() == 1 {
+		returnType = hw.goCTypeName(results.At(0).Type())
+	} else {
+		panic("multiple return values can't export to C header")
+	}
+
+	// Generate parameter types
+	var paramTypes []string
+	params := sig.Params()
+	if params == nil || params.Len() == 0 {
+		paramTypes = []string{"void"}
+	} else {
+		for i := 0; i < params.Len(); i++ {
+			paramType := hw.goCTypeName(params.At(i).Type())
+			paramTypes = append(paramTypes, paramType)
+		}
+	}
+
+	// Return function pointer type: returnType (*)(paramType1, paramType2, ...)
+	return fmt.Sprintf("%s (*)(%s)", returnType, strings.Join(paramTypes, ", "))
+}
+
 // generateTypedef generates C typedef declaration for complex types
 func (hw *cheaderWriter) generateTypedef(t types.Type) string {
 	switch typ := t.(type) {
@@ -248,10 +283,41 @@ func (hw *cheaderWriter) generateTypedef(t types.Type) string {
 			// For named struct types, generate the typedef directly
 			return hw.generateNamedStructTypedef(typ, structType)
 		}
+
+		cTypeName := hw.goCTypeName(typ)
+
+		// Special handling for function types
+		if sig, ok := underlying.(*types.Signature); ok {
+			// Generate return type
+			var returnType string
+			results := sig.Results()
+			if results == nil || results.Len() == 0 {
+				returnType = "void"
+			} else if results.Len() == 1 {
+				returnType = hw.goCTypeName(results.At(0).Type())
+			} else {
+				panic("multiple return values can't export to C header")
+			}
+
+			// Generate parameter types
+			var paramTypes []string
+			params := sig.Params()
+			if params == nil || params.Len() == 0 {
+				paramTypes = []string{"void"}
+			} else {
+				for i := 0; i < params.Len(); i++ {
+					paramType := hw.goCTypeName(params.At(i).Type())
+					paramTypes = append(paramTypes, paramType)
+				}
+			}
+
+			// Generate proper function pointer typedef: typedef returnType (*typeName)(params);
+			return fmt.Sprintf("typedef %s (*%s)(%s);", returnType, cTypeName, strings.Join(paramTypes, ", "))
+		}
+
 		// For other named types, create a typedef to the underlying type
 		underlyingCType := hw.goCTypeName(underlying)
 		if underlyingCType != "" {
-			cTypeName := hw.goCTypeName(typ)
 			return fmt.Sprintf("typedef %s %s;", underlyingCType, cTypeName)
 		}
 	}
@@ -312,6 +378,75 @@ func (hw *cheaderWriter) ensureArrayStruct(arr *types.Array) string {
 	return structName
 }
 
+// generateParameterDeclaration generates C parameter declaration for function parameters
+func (hw *cheaderWriter) generateParameterDeclaration(paramType types.Type, paramName string) string {
+	var cType string
+
+	switch typ := paramType.(type) {
+	case *types.Array:
+		// Handle multidimensional arrays by collecting all dimensions
+		var dimensions []int64
+		baseType := types.Type(typ)
+
+		// Traverse all array dimensions
+		for {
+			if arr, ok := baseType.(*types.Array); ok {
+				dimensions = append(dimensions, arr.Len())
+				baseType = arr.Elem()
+			} else {
+				break
+			}
+		}
+
+		// Get base element type
+		elemType := hw.goCTypeName(baseType)
+
+		// For parameters, preserve all array dimensions
+		// In C, array parameters need special handling for syntax
+		cType = elemType
+
+		// Store dimensions for later use with parameter name
+		var dimStr strings.Builder
+		for _, dim := range dimensions {
+			dimStr.WriteString(fmt.Sprintf("[%d]", dim))
+		}
+
+		// For single dimension, we can use pointer syntax
+		if len(dimensions) == 1 {
+			cType = elemType + "*"
+		} else {
+			// For multi-dimensional, we need to handle it when adding parameter name
+			// Store the dimension info in a special way
+			cType = elemType + "ARRAY_DIMS" + dimStr.String()
+		}
+	case *types.Pointer:
+		pointeeType := hw.goCTypeName(typ.Elem())
+		cType = pointeeType + "*"
+	default:
+		// Regular types
+		cType = hw.goCTypeName(paramType)
+	}
+
+	// Handle special array dimension syntax
+	if strings.Contains(cType, "ARRAY_DIMS") {
+		parts := strings.Split(cType, "ARRAY_DIMS")
+		elemType := parts[0]
+		dimStr := parts[1]
+
+		if paramName == "" {
+			// For unnamed parameters, keep dimension info: type[dim1][dim2]
+			return elemType + dimStr
+		}
+		// For named parameters, use proper array syntax: type name[dim1][dim2]
+		return elemType + " " + paramName + dimStr
+	}
+
+	if paramName == "" {
+		return cType
+	}
+	return cType + " " + paramName
+}
+
 // generateFieldDeclaration generates C field declaration with correct array syntax
 func (hw *cheaderWriter) generateFieldDeclaration(fieldType types.Type, fieldName string) string {
 	switch fieldType.(type) {
@@ -461,15 +596,9 @@ func (hw *cheaderWriter) writeFunctionDecl(fullName, linkName string, fn ssa.Fun
 		}
 
 		paramName := param.Name()
-		if paramName == "" {
-			paramName = fmt.Sprintf("param%d", i)
-		}
 
-		// Use generateFieldDeclaration logic for consistent parameter syntax
+		// Generate parameter declaration
-		paramDecl := hw.generateFieldDeclaration(paramType, paramName)
+		paramDecl := hw.generateParameterDeclaration(paramType, paramName)
-		// Remove the leading spaces and semicolon to get just the declaration
-		paramDecl = strings.TrimSpace(paramDecl)
-		paramDecl = strings.TrimSuffix(paramDecl, ";")
 		params = append(params, paramDecl)
 	}
 
@@ -571,7 +700,7 @@ func genHeader(p ssa.Program, pkgs []ssa.Package, w io.Writer) error {
 			link := exports[name] // link is cName
 			fn := pkg.FuncOf(link)
 			if fn == nil {
-				continue
+				return fmt.Errorf("function %s not found", link)
 			}
 
 			// Write function declaration with proper C types

internal/header/header_test.go

@@ -235,7 +235,7 @@ func TestGoCTypeName(t *testing.T) {
 		{
 			name:     "signature type",
 			goType:   types.NewSignature(nil, nil, nil, false),
-			expected: "void*",
+			expected: "void (*)(void)",
 		},
 	}
 
@@ -504,6 +504,153 @@ func TestProcessDependentTypesEdgeCases(t *testing.T) {
 	if err != nil {
 		t.Errorf("processSignatureTypes(no results) error = %v", err)
 	}
+
+	// Test function type (callback) parameters - IntCallback
+	intCallbackParams := types.NewTuple(types.NewVar(0, nil, "x", types.Typ[types.Int]))
+	intCallbackResults := types.NewTuple(types.NewVar(0, nil, "", types.Typ[types.Int]))
+	intCallbackSig := types.NewSignatureType(nil, nil, nil, intCallbackParams, intCallbackResults, false)
+	err = hw.writeTypedefRecursive(intCallbackSig, make(map[string]bool))
+	if err != nil {
+		t.Errorf("writeTypedefRecursive(IntCallback) error = %v", err)
+	}
+
+	// Test function type (callback) parameters - StringCallback
+	stringCallbackParams := types.NewTuple(types.NewVar(0, nil, "s", types.Typ[types.String]))
+	stringCallbackResults := types.NewTuple(types.NewVar(0, nil, "", types.Typ[types.String]))
+	stringCallbackSig := types.NewSignatureType(nil, nil, nil, stringCallbackParams, stringCallbackResults, false)
+	err = hw.writeTypedefRecursive(stringCallbackSig, make(map[string]bool))
+	if err != nil {
+		t.Errorf("writeTypedefRecursive(StringCallback) error = %v", err)
+	}
+
+	// Test function type (callback) parameters - VoidCallback
+	voidCallbackSig := types.NewSignatureType(nil, nil, nil, nil, nil, false)
+	err = hw.writeTypedefRecursive(voidCallbackSig, make(map[string]bool))
+	if err != nil {
+		t.Errorf("writeTypedefRecursive(VoidCallback) error = %v", err)
+	}
+
+	// Test Named function type - this should trigger the function typedef generation
+	pkg := types.NewPackage("test", "test")
+	callbackParams := types.NewTuple(types.NewVar(0, nil, "x", types.Typ[types.Int]))
+	callbackSig := types.NewSignatureType(nil, nil, nil, callbackParams, nil, false)
+	callbackTypeName := types.NewTypeName(0, pkg, "Callback", nil)
+	namedCallback := types.NewNamed(callbackTypeName, callbackSig, nil)
+
+	// Test Named function type with no parameters - NoParamCallback func() int
+	noParamCallbackResults := types.NewTuple(types.NewVar(0, nil, "", types.Typ[types.Int]))
+	noParamCallbackSig := types.NewSignatureType(nil, nil, nil, nil, noParamCallbackResults, false)
+	noParamCallbackTypeName := types.NewTypeName(0, pkg, "NoParamCallback", nil)
+	namedNoParamCallback := types.NewNamed(noParamCallbackTypeName, noParamCallbackSig, nil)
+
+	err = hw.writeTypedef(namedCallback)
+	if err != nil {
+		t.Errorf("writeTypedef(named function) error = %v", err)
+	}
+
+	err = hw.writeTypedef(namedNoParamCallback)
+	if err != nil {
+		t.Errorf("writeTypedef(no param callback) error = %v", err)
+	}
+
+	// Verify the generated typedef contains function pointer syntax
+	output := hw.typeBuf.String()
+	if !strings.Contains(output, "test_Callback") {
+		t.Errorf("Expected named function typedef in output")
+	}
+	if !strings.Contains(output, "(*test_Callback)") {
+		t.Errorf("Expected function pointer syntax in typedef: %s", output)
+	}
+	if !strings.Contains(output, "test_NoParamCallback") {
+		t.Errorf("Expected no-param callback typedef in output")
+	}
+	if !strings.Contains(output, "(*test_NoParamCallback)(void)") {
+		t.Errorf("Expected no-param function pointer syntax in typedef: %s", output)
+	}
+
+	// Test function signature with unnamed parameters (like //export ProcessThreeUnnamedParams)
+	unnamedParams := types.NewTuple(
+		types.NewVar(0, nil, "", types.Typ[types.Int]),
+		types.NewVar(0, nil, "", types.Typ[types.String]),
+		types.NewVar(0, nil, "", types.Typ[types.Bool]),
+	)
+	unnamedResults := types.NewTuple(types.NewVar(0, nil, "", types.Typ[types.Float64]))
+	unnamedSig := types.NewSignatureType(nil, nil, nil, unnamedParams, unnamedResults, false)
+	err = hw.writeTypedefRecursive(unnamedSig, make(map[string]bool))
+	if err != nil {
+		t.Errorf("writeTypedefRecursive(unnamed params) error = %v", err)
+	}
+}
+
+// Test generateParameterDeclaration function
+func TestGenerateParameterDeclaration(t *testing.T) {
+	prog := ssa.NewProgram(nil)
+	hw := newCHeaderWriter(prog)
+
+	tests := []struct {
+		name      string
+		paramType types.Type
+		paramName string
+		expected  string
+	}{
+		{
+			name:      "basic type with name",
+			paramType: types.Typ[types.Int],
+			paramName: "x",
+			expected:  "intptr_t x",
+		},
+		{
+			name:      "basic type without name",
+			paramType: types.Typ[types.Int],
+			paramName: "",
+			expected:  "intptr_t",
+		},
+		{
+			name:      "array type with name",
+			paramType: types.NewArray(types.Typ[types.Int], 5),
+			paramName: "arr",
+			expected:  "intptr_t* arr",
+		},
+		{
+			name:      "array type without name",
+			paramType: types.NewArray(types.Typ[types.Int], 5),
+			paramName: "",
+			expected:  "intptr_t*",
+		},
+		{
+			name:      "multidimensional array with name",
+			paramType: types.NewArray(types.NewArray(types.Typ[types.Int], 4), 3),
+			paramName: "matrix",
+			expected:  "intptr_t matrix[3][4]",
+		},
+		{
+			name:      "multidimensional array without name",
+			paramType: types.NewArray(types.NewArray(types.Typ[types.Int], 4), 3),
+			paramName: "",
+			expected:  "intptr_t[3][4]",
+		},
+		{
+			name:      "pointer type with name",
+			paramType: types.NewPointer(types.Typ[types.Int]),
+			paramName: "ptr",
+			expected:  "intptr_t* ptr",
+		},
+		{
+			name:      "pointer type without name",
+			paramType: types.NewPointer(types.Typ[types.Int]),
+			paramName: "",
+			expected:  "intptr_t*",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := hw.generateParameterDeclaration(tt.paramType, tt.paramName)
+			if got != tt.expected {
+				t.Errorf("generateParameterDeclaration() = %q, want %q", got, tt.expected)
+			}
+		})
+	}
 }
 
 // Test generateNamedStructTypedef with forward declaration

ssa/expr.go

@@ -1344,7 +1344,7 @@ func (b Builder) PrintEx(ln bool, args ...Expr) (ret Expr) {
 // -----------------------------------------------------------------------------
 
 func checkExpr(v Expr, t types.Type, b Builder) Expr {
-	if st, ok := t.Underlying().(*types.Struct); ok && isClosure(st) {
+	if st, ok := t.Underlying().(*types.Struct); ok && IsClosure(st) {
 		if v.kind != vkClosure {
 			return b.Pkg.closureStub(b, t, v)
 		}

ssa/type.go

@@ -411,7 +411,7 @@ func (p Program) toLLVMNamedStruct(name string, raw *types.Struct) llvm.Type {
 func (p Program) toLLVMStruct(raw *types.Struct) (ret llvm.Type, kind valueKind) {
 	fields := p.toLLVMFields(raw)
 	ret = p.ctx.StructType(fields, false)
-	if isClosure(raw) {
+	if IsClosure(raw) {
 		kind = vkClosure
 	} else {
 		kind = vkStruct
@@ -419,7 +419,7 @@ func (p Program) toLLVMStruct(raw *types.Struct) (ret llvm.Type, kind valueKind)
 	return
 }
 
-func isClosure(raw *types.Struct) bool {
+func IsClosure(raw *types.Struct) bool {
 	n := raw.NumFields()
 	if n == 2 {
 		f1, f2 := raw.Field(0), raw.Field(1)
@@ -508,7 +508,7 @@ func (p Program) toNamed(raw *types.Named) Type {
 	case *types.Struct:
 		name := p.llvmNameOf(raw)
 		kind := vkStruct
-		if isClosure(t) {
+		if IsClosure(t) {
 			kind = vkClosure
 		}
 		return &aType{p.toLLVMNamedStruct(name, t), rawType{raw}, kind}

ssa/type_cvt.go

@@ -92,7 +92,7 @@ func (p goTypes) cvtType(typ types.Type) (raw types.Type, cvt bool) {
 			return types.NewMap(key, elem), true
 		}
 	case *types.Struct:
-		if isClosure(t) {
+		if IsClosure(t) {
 			return typ, false
 		}
 		return p.cvtStruct(t)