Surround declaration of functions with FOUG_C_LINKAGE_BEGIN and FOUG_C_LINKAGE_END

This avoids linking errors with use of FougDataX in C++ programs

src/endian.h

@@ -3,6 +3,8 @@
 
 #include "global.h"
 
+FOUG_C_LINKAGE_BEGIN
+
 /*! This enum identifies endian representations of numbers */
 enum foug_endianness
 {
@@ -17,4 +19,6 @@ typedef enum foug_endianness foug_endianness_t;
 /*! Returns endianness (byte order) of the host's CPU architecture */
 FOUG_LIB_EXPORT foug_endianness_t foug_host_endianness();
 
+FOUG_C_LINKAGE_END
+
 #endif /* FOUG_ENDIAN_H */

src/error.h

@@ -3,6 +3,8 @@
 
 #include "global.h"
 
+FOUG_C_LINKAGE_BEGIN
+
 /*! This enum defines common errors */
 enum foug_datax_error
 {
@@ -33,4 +35,6 @@ FOUG_LIB_EXPORT foug_bool_t foug_datax_no_error(int code);
 /*! Returns true if \p code != FOUG_DATAX_NO_ERROR */
 FOUG_LIB_EXPORT foug_bool_t foug_datax_error(int code);
 
+FOUG_C_LINKAGE_END
+
 #endif /* FOUG_DATAX_C_ERROR_H */

src/global.h

@@ -73,4 +73,12 @@ typedef double foug_real64_t;
 # endif
 #endif /* !FOUG_INLINE */
 
+#ifdef __cplusplus
+# define FOUG_C_LINKAGE_BEGIN extern "C" {
+# define FOUG_C_LINKAGE_END   }
+#else
+# define FOUG_C_LINKAGE_BEGIN
+# define FOUG_C_LINKAGE_END
+#endif /* __cplusplus */
+
 #endif /* FOUG_C_GLOBAL_H */

src/libstl/stl_format.h

@@ -4,6 +4,8 @@
 #include "stl_global.h"
 #include "../stream.h"
 
+FOUG_C_LINKAGE_BEGIN
+
 /*! This enums defines the various STL formats */
 enum foug_stl_format
 {
@@ -18,4 +20,6 @@ typedef enum foug_stl_format foug_stl_format_t;
 FOUG_DATAX_LIBSTL_EXPORT
 foug_stl_format_t foug_stl_get_format(foug_stream_t* stream, size_t data_size);
 
+FOUG_C_LINKAGE_END
+
 #endif /* FOUG_LIBSTL_FORMAT_H */

src/libstl/stl_io.h

@@ -7,6 +7,8 @@
 #include "../endian.h"
 #include "../transfer.h"
 
+FOUG_C_LINKAGE_BEGIN
+
 /*
  *  STL ascii
  */
@@ -37,4 +39,6 @@ FOUG_DATAX_LIBSTL_EXPORT int foug_stlb_write(const foug_stl_geom_t* geom,
                                              const uint8_t*         header_data,
                                              foug_endianness_t      byte_order);
 
+FOUG_C_LINKAGE_END
+
 #endif /* FOUG_DATAX_LIBSTL_STL_IO_H */

src/stream.h

@@ -4,6 +4,8 @@
 #include "global.h"
 #include <stdio.h>
 
+FOUG_C_LINKAGE_BEGIN
+
 /*! Stream that can get input from an arbitrary data source or can write output to an arbitrary
  *  data sink
  */
@@ -55,4 +57,6 @@ FOUG_LIB_EXPORT size_t foug_stream_write(foug_stream_t* stream,
                                          size_t size,
                                          size_t count);
 
+FOUG_C_LINKAGE_END
+
 #endif /* FOUG_C_STREAM_H */

src/task_control.h

@@ -4,6 +4,8 @@
 #include "global.h"
 #include "memory.h"
 
+FOUG_C_LINKAGE_BEGIN
+
 /*! Provides control over a general task.
  *
  *  "Control" here means task progress handling and interruption request (abort).
@@ -26,4 +28,6 @@ FOUG_LIB_EXPORT foug_bool_t foug_task_control_handle_progress(foug_task_control_
 /*! Utility function that converts \p value as a percentage */
 FOUG_LIB_EXPORT uint8_t foug_percentage(size_t range_min, size_t range_max, size_t value);
 
+FOUG_C_LINKAGE_END
+
 #endif /* FOUG_C_TASK_CONTROL_H */