Add code to CI to verify signed/unsigned char

Make sure that our attempt to test both signed and unsigned char is
actually right.

2 files changed, 12 insertions, 0 deletions

diff --git a/qpdf/CMakeLists.txt b/qpdf/CMakeLists.txt
index 69eb0058..d089957b 100644
--- a/qpdf/CMakeLists.txt
+++ b/qpdf/CMakeLists.txt
@@ -3,6 +3,7 @@ set(MAIN_CXX_PROGRAMS
   fix-qdf
   pdf_from_scratch
   sizes
+  test_char_sign
   test_driver
   test_large_file
   test_many_nulls
diff --git a/qpdf/test_char_sign.cc b/qpdf/test_char_sign.cc
new file mode 100644
index 00000000..caaa7527
--- /dev/null
+++ b/qpdf/test_char_sign.cc
@@ -0,0 +1,11 @@
+#include <cstdio>
+int main()
+{
+    char ch = '\xf7';
+    if (ch < 0) {
+        printf("char is signed\n");
+    } else {
+        printf("char is unsigned\n");
+    }
+    return 0;
+}