1 files changed, 25 insertions, 0 deletions
diff --git a/examples/extend-c-api.h b/examples/extend-c-api.h
new file mode 100644
index 00000000..3b2d12d4
--- /dev/null
+++ b/examples/extend-c-api.h
@@ -0,0 +1,25 @@
+#ifndef EXAMPLE_C_EXTEND_H
+#define EXAMPLE_C_EXTEND_H
+
+/*
+ * This is an example of how to write C++ functions and make them usable with the qpdf C API. It
+ * consists of three files:
+ * - extend-c-api.h -- a plain C header file
+ * - extend-c-api.c -- a C program that calls the function
+ * - extend-c-api.cc -- a C++ file that implements the function
+ */
+#include <qpdf/qpdf-c.h>
+
+/* Declare your custom function to return QPDF_ERROR_CODE and take qpdf_data and anything else you
+ * need. Any errors are retrievable through the qpdf C APIs normal error-handling mechanism.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+    QPDF_ERROR_CODE num_pages(qpdf_data qc, int* npages);
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* EXAMPLE_C_EXTEND_H */