Index: src/OFApplication.h
==================================================================
--- src/OFApplication.h
+++ src/OFApplication.h
@@ -163,6 +163,12 @@
 @end
 
 @interface OFObject (OFApplicationDelegate) <OFApplicationDelegate>
 @end
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern int of_application_main(int*, char**[], Class);
+#ifdef __cplusplus
+}
+#endif

Index: src/OFBlock.h
==================================================================
--- src/OFBlock.h
+++ src/OFBlock.h
@@ -57,12 +57,18 @@
 	OF_BLOCK_FIELD_IS_BYREF	 =   8,
 	OF_BLOCK_FIELD_IS_WEAK	 =  16,
 	OF_BLOCK_BYREF_CALLER	 = 128,
 };
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern void* _Block_copy(const void*);
 extern void _Block_release(const void*);
+#ifdef __cplusplus
+}
+#endif
 
 #ifndef Block_copy
 # define Block_copy(x) ((__typeof__(x))_Block_copy((const void*)(x)))
 #endif
 #ifndef Block_release

Index: src/OFConstantString.h
==================================================================
--- src/OFConstantString.h
+++ src/OFConstantString.h
@@ -15,13 +15,19 @@
  */
 
 #import "OFString.h"
 
 #ifdef OF_APPLE_RUNTIME
+# ifdef __cplusplus
+extern "C" {
+#endif
 extern void *_OFConstantStringClassReference;
+# ifdef __cplusplus
+}
+#endif
 #endif
 
 /**
  * \brief A class for storing constant strings using the \@"" literal.
  */
 @interface OFConstantString: OFString
 @end

Index: src/OFDictionary.h
==================================================================
--- src/OFDictionary.h
+++ src/OFDictionary.h
@@ -213,6 +213,12 @@
 @interface OFDictionaryKeyEnumerator: OFDictionaryEnumerator
 @end
 
 #import "OFMutableDictionary.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern struct of_dictionary_bucket of_dictionary_deleted_bucket;
+#ifdef __cplusplus
+}
+#endif

Index: src/OFFile.h
==================================================================
--- src/OFFile.h
+++ src/OFFile.h
@@ -19,11 +19,17 @@
 #import "OFSeekableStream.h"
 
 @class OFArray;
 @class OFDate;
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern void of_log(OFConstantString*, ...);
+#ifdef __cplusplus
+}
+#endif
 
 /**
  * \brief A class which provides functions to read, write and manipulate files.
  */
 @interface OFFile: OFSeekableStream
@@ -204,8 +210,14 @@
  *	     It is not closed when the OFFile object is deallocated!
  */
 - initWithFileDescriptor: (int)fd;
 @end
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern OFFile *of_stdin;
 extern OFFile *of_stdout;
 extern OFFile *of_stderr;
+#ifdef __cplusplus
+}
+#endif

Index: src/OFObject.h
==================================================================
--- src/OFObject.h
+++ src/OFObject.h
@@ -406,6 +406,12 @@
  * \return The result of the comparison
  */
 - (of_comparison_result_t)compare: (id)obj;
 @end
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern size_t of_pagesize;
+#ifdef __cplusplus
+}
+#endif

Index: src/OFString+Hashing.h
==================================================================
--- src/OFString+Hashing.h
+++ src/OFString+Hashing.h
@@ -14,11 +14,17 @@
  * file.
  */
 
 #import "OFString.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern int _OFString_Hashing_reference;
+#ifdef __cplusplus
+}
+#endif
 
 /**
  * The OFString (OFHashing) category provides methods to calculate hashes for
  * strings.
  */

Index: src/OFString+URLEncoding.h
==================================================================
--- src/OFString+URLEncoding.h
+++ src/OFString+URLEncoding.h
@@ -14,11 +14,17 @@
  * file.
  */
 
 #import "OFString.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern int _OFString_URLEncoding_reference;
+#ifdef __cplusplus
+}
+#endif
 
 /**
  * \brief A category which provides URL encoding and decoding.
  */
 @interface OFString (URLEncoding)

Index: src/OFString+XMLEscaping.h
==================================================================
--- src/OFString+XMLEscaping.h
+++ src/OFString+XMLEscaping.h
@@ -14,11 +14,17 @@
  * file.
  */
 
 #import "OFString.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern int _OFString_XMLEscaping_reference;
+#ifdef __cplusplus
+}
+#endif
 
 /**
  * \brief A category to escape strings for use in an XML document.
  */
 @interface OFString (XMLEscaping)

Index: src/OFString+XMLUnescaping.h
==================================================================
--- src/OFString+XMLUnescaping.h
+++ src/OFString+XMLUnescaping.h
@@ -14,11 +14,17 @@
  * file.
  */
 
 #import "OFString.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern int _OFString_XMLUnescaping_reference;
+#ifdef __cplusplus
+}
+#endif
 
 #ifdef OF_HAVE_BLOCKS
 typedef OFString* (^of_string_xml_unescaping_block_t)(OFString *str,
     OFString *entity);
 #endif

Index: src/OFString.h
==================================================================
--- src/OFString.h
+++ src/OFString.h
@@ -29,15 +29,21 @@
 	OF_STRING_ENCODING_ISO_8859_1,
 	OF_STRING_ENCODING_ISO_8859_15,
 	OF_STRING_ENCODING_WINDOWS_1252
 } of_string_encoding_t;
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern int of_string_check_utf8(const char*, size_t);
 extern size_t of_string_unicode_to_utf8(of_unichar_t, char*);
 extern size_t of_string_utf8_to_unicode(const char*, size_t, of_unichar_t*);
 extern size_t of_string_position_to_index(const char*, size_t);
 extern size_t of_string_index_to_position(const char*, size_t, size_t);
+#ifdef __cplusplus
+}
+#endif
 
 @class OFArray;
 
 /**
  * \brief A class for handling strings.

Index: src/asprintf.h
==================================================================
--- src/asprintf.h
+++ src/asprintf.h
@@ -17,8 +17,14 @@
 #import "objfw-defs.h"
 
 #ifndef OF_HAVE_ASPRINTF
 # include <stdarg.h>
 
+# ifdef __cplusplus
+extern "C" {
+# endif
 extern int asprintf(char**, const char*, ...);
 extern int vasprintf(char**, const char*, va_list);
+# ifdef __cplusplus
+}
+# endif
 #endif

Index: src/of_asprintf.h
==================================================================
--- src/of_asprintf.h
+++ src/of_asprintf.h
@@ -16,7 +16,13 @@
 
 #include <stdarg.h>
 
 #import "macros.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern int of_asprintf(char**, const char*, ...);
 extern int of_vasprintf(char**, const char*, va_list);
+#ifdef __cplusplus
+}
+#endif

Index: src/unicode.h
==================================================================
--- src/unicode.h
+++ src/unicode.h
@@ -18,11 +18,17 @@
 
 #define OF_UNICODE_UPPER_TABLE_SIZE 0x105
 #define OF_UNICODE_LOWER_TABLE_SIZE 0x105
 #define OF_UNICODE_CASEFOLDING_TABLE_SIZE 0x105
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 extern const of_unichar_t* const
     of_unicode_upper_table[OF_UNICODE_UPPER_TABLE_SIZE];
 extern const of_unichar_t* const
     of_unicode_lower_table[OF_UNICODE_LOWER_TABLE_SIZE];
 extern const of_unichar_t* const
     of_unicode_casefolding_table[OF_UNICODE_CASEFOLDING_TABLE_SIZE];
+#ifdef __cplusplus
+}
+#endif