4 files changed, 12 insertions, 0 deletions
diff --git a/testdata/cgo/main.c b/testdata/cgo/main.c
index 7fb702ed6..4a5bd6b9c 100644
--- a/testdata/cgo/main.c
+++ b/testdata/cgo/main.c
@@ -1,5 +1,6 @@
 #include <math.h>
 #include "main.h"
+#include <stdio.h>
 
 int global = 3;
 bool globalBool = 1;
@@ -72,3 +73,7 @@ void arraydecay(int buf1[5], int buf2[3][8], int buf3[4][7][2]) {
 double doSqrt(double x) {
 	return sqrt(x);
 }
+
+void printf_single_int(char *format, int arg) {
+	printf(format, arg);
+}
diff --git a/testdata/cgo/main.go b/testdata/cgo/main.go
index fa3380bce..ddd1992e2 100644
--- a/testdata/cgo/main.go
+++ b/testdata/cgo/main.go
@@ -179,6 +179,10 @@ func main() {
 	// libc: test basic stdio functionality
 	putsBuf := []byte("line written using C puts\x00")
 	C.puts((*C.char)(unsafe.Pointer(&putsBuf[0])))
+
+	// libc: test whether printf works in C.
+	printfBuf := []byte("line written using C printf with value=%d\n\x00")
+	C.printf_single_int((*C.char)(unsafe.Pointer(&printfBuf[0])), -21)
 }
 
 func printUnion(union C.joined_t) C.joined_t {
diff --git a/testdata/cgo/main.h b/testdata/cgo/main.h
index f5405ade6..e7c64ffc3 100644
--- a/testdata/cgo/main.h
+++ b/testdata/cgo/main.h
@@ -152,3 +152,5 @@ typedef int arraydecay_buf3[4][7][2];
 void arraydecay(int buf1[5], int buf2[3][8], arraydecay_buf3 buf3);
 
 double doSqrt(double);
+
+void printf_single_int(char *format, int arg);
diff --git a/testdata/cgo/out.txt b/testdata/cgo/out.txt
index ae92c87a7..4ea45d864 100644
--- a/testdata/cgo/out.txt
+++ b/testdata/cgo/out.txt
@@ -77,3 +77,4 @@ copied string: foobar
 CGo sqrt(3): +1.732051e+000
 C   sqrt(3): +1.732051e+000
 line written using C puts
+line written using C printf with value=-21