UnitaryTests/SCardCancel.c: test for SCardCancel

Check that the fix in 81d52b98d84be900c6a6532d10d1fe88eac092cf works as
expected.

UnitaryTests/Makefile

@@ -10,6 +10,7 @@ CFLAGS := -Wall -O2 -g -DVERSION=\"$(VERSION)\" $(PCSC_CFLAGS)
 LDLIBS := $(PCSC_LDLIBS)
 
 PROGRAMS := SCardBeginTransaction \
+	SCardCancel \
 	BufferOverflow_SCardGetAttrib \
 	BufferOverflow_SCardTransmit \
 	BufferOverflow_SCardControl \

UnitaryTests/SCardCancel.c

@@ -0,0 +1,88 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <pthread.h>
+
+#ifdef __APPLE__
+#include <PCSC/winscard.h>
+#include <PCSC/wintypes.h>
+#else
+#include <winscard.h>
+#endif
+
+#define CHECK(f, rv) printf(f ":[0x%08lX] %s\n", rv, pcsc_stringify_error(rv))
+
+#define GREEN "\33[32m"
+#define BRIGHT_RED "\33[01;31m"
+#define NORMAL "\33[0m"
+
+static SCARDCONTEXT context;
+
+static void *canceler_thread(void *arg) {
+    LONG ret;
+
+    getchar();
+
+    printf("Calling SCardCancel...\n");
+    ret = SCardCancel(context);
+    CHECK("SCardCancel", ret);
+
+    return NULL;
+}
+
+int main(void) {
+    LONG ret;
+	int delay = 3;
+
+    ret = SCardEstablishContext(SCARD_SCOPE_USER, NULL, NULL, &context);
+    CHECK("SCardEstablishContext", ret);
+
+    // Spawn a thread which waits for a key-press then cancels the operation.
+    pthread_t thread;
+    ret = pthread_create(&thread, NULL, canceler_thread, NULL);
+
+	printf(GREEN "Press Enter to cancel within %d seconds\n" NORMAL, delay);
+
+    // Set up the blocking call, and wait for cancel or timeout.
+    printf("Entering blocking call\n");
+    SCARD_READERSTATE reader_states[] = {
+        {
+            .szReader = "\\\\?PnP?\\Notification",
+            .pvUserData = NULL,
+            .dwCurrentState = SCARD_STATE_UNAWARE,
+            .dwEventState = SCARD_STATE_UNAWARE,
+        },
+    };
+
+    ret = SCardGetStatusChange(context, delay * 1000, reader_states, 1);
+	CHECK("SCardGetStatusChange", ret);
+    switch (ret) {
+    case SCARD_S_SUCCESS:
+        printf("Blocking call exited normally\n");
+        break;
+
+    case SCARD_E_CANCELLED:
+		/* this should be the correct returned value */
+        printf("Blocking call canceled\n");
+        break;
+
+    case SCARD_E_TIMEOUT:
+        printf("Blocking call timed out\n");
+        break;
+
+    default:
+        fprintf(stderr, "Failed to get status changes: %ld", ret);
+        break;
+    }
+	if (SCARD_E_CANCELLED != ret)
+		printf(BRIGHT_RED "ERROR: Something wrong happened!\n" NORMAL);
+	else
+		printf(GREEN "Good\n" NORMAL);
+
+	ret = SCardReleaseContext(context);
+	CHECK("SCardReleaseContext", ret);
+
+    printf("Waiting thread...\n");
+	pthread_join(thread, NULL);
+
+    return 0;
+}