Add spec for varargs functions returning struct-by-value. From Scott Brooks <scott@scottbrooks.ca>

2 files changed, 37 insertions, 0 deletions

diff --git a/libtest/StructTest.c b/libtest/StructTest.c
index ca55638..675dbd6 100644
--- a/libtest/StructTest.c
+++ b/libtest/StructTest.c
@@ -30,6 +30,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include <string.h>
+#include <stdarg.h>
 
 typedef char s8;
 typedef short s16;
@@ -215,3 +216,26 @@ struct_s8s32_s64_ret_s64(struct s8s32 s, long long s64)
 {
     return s64;
 }
+
+// Pass a char *, copy into buffer length struct
+struct struct_string {
+    char *bytes;
+    int len;
+};
+
+struct struct_string
+struct_varargs_ret_struct_string(int len, ...)
+{
+    struct struct_string ss;
+    va_list vl;
+
+    va_start(vl, len);
+
+    ss.len = len;
+    ss.bytes = va_arg(vl, char *);
+
+    va_end(vl);
+
+    return ss;
+}
+
diff --git a/spec/ffi/struct_spec.rb b/spec/ffi/struct_spec.rb
index d5f1cd8..6deafad 100644
--- a/spec/ffi/struct_spec.rb
+++ b/spec/ffi/struct_spec.rb
@@ -387,12 +387,18 @@ describe FFI::Struct, ' by value'  do
     class S8S32 < FFI::Struct
       layout :s8, :char, :s32, :int
     end
+
+    class StructString < FFI::Struct
+      layout :bytes, :string, :len, :int
+    end
+
     attach_function :struct_return_s8s32, [ ], S8S32.by_value
     attach_function :struct_s8s32_set, [ :char, :int ], S8S32.by_value
     attach_function :struct_s8s32_get_s8, [ S8S32.by_value ], :char
     attach_function :struct_s8s32_get_s32, [ S8S32.by_value ], :int
     attach_function :struct_s8s32_s32_ret_s32, [ S8S32.by_value, :int ], :int
     attach_function :struct_s8s32_s64_ret_s64, [ S8S32.by_value, :long_long ], :long_long
+    attach_function :struct_varargs_ret_struct_string, [ :int, :varargs ], StructString.by_value
   end
 
   it 'return using pre-set values' do
@@ -430,6 +436,13 @@ describe FFI::Struct, ' by value'  do
 
     LibTest.struct_s8s32_s64_ret_s64(s, 0xdeadcafebabe).should == 0xdeadcafebabe
   end
+
+  it 'varargs returning a struct' do
+    string = "test"
+    s = LibTest.struct_varargs_ret_struct_string(4, :string, string)
+    s[:len].should == string.length
+    s[:bytes].should == string
+  end
 end
 
 describe FFI::Struct, ' with an array field'  do