--- a/Symbian3/SDK/Source/GUID-006C503D-1E52-450D-A4DA-8C19B141E09F.dita Wed Mar 31 11:11:55 2010 +0100
+++ b/Symbian3/SDK/Source/GUID-006C503D-1E52-450D-A4DA-8C19B141E09F.dita Fri Jun 11 12:39:03 2010 +0100
@@ -1,137 +1,137 @@
-<?xml version="1.0" encoding="utf-8"?>
-<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
-<!-- This component and the accompanying materials are made available under the terms of the License
-"Eclipse Public License v1.0" which accompanies this distribution,
-and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
-<!-- Initial Contributors:
- Nokia Corporation - initial contribution.
-Contributors:
--->
-<!DOCTYPE concept
- PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
-<concept id="GUID-006C503D-1E52-450D-A4DA-8C19B141E09F" xml:lang="en"><title>Introduction
-to Intermixing C and C++</title><shortdesc>When porting an open source application or any C (or C++) applications
-on top of Symbian/S60 using P.I.P.S., the developer will come across situations
-where C and C++ (and Symbian C++ as well) codes will be used together. The
-open source community implements a vast number of libraries that export C
-APIs to the user of such libraries.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
-<section id="GUID-88635D46-AEF6-4E8E-969D-D3E56941F289-GENID-1-8-1-11-1-1-5-1-3-1-7-1-4-1-4-1-3-1"> <title>When
-and why to use C linkage</title> <p>While porting such applications,
-if developers have to intermix C and C++ code, they then have to depend on
-C++ language features like extern "C" for giving C linkage to some set of
-APIs. This is required because C and C++ compilers handle function prototype
-in a different way. C++ compilers use name mangling, (or name decoration)
-to generate unique names for identifiers in a program. It is because of this
-technique, in C++, that it is possible to overload any functions (this requires
-that all the overloaded functions should have a different argument list).
-The C++ mangled name for any identifier contains all the necessary information
-that may be needed by the linker, such as linkage type, scope, calling convention,
-and others.</p><p>All identifiers (function names or variable names) declared
-or defined in C++ source or headers are subject to name mangling. When it
-comes to C, however, there is nothing called name mangling or overloading.
-It applies when the developer tries to use C APIs by including corresponding
-headers. To avoid name mangling, the developer should mention explicitly that
-those APIs are C APIs, by using the extern "C" keyword. </p> </section>
-<section id="GUID-88635D46-AEF6-4E8E-969D-D3E56941F289-GENID-1-8-1-11-1-1-5-1-3-1-7-1-4-1-4-1-3-2"> <title>Syntax
-of extern C</title> <p>The syntax of extern "C" is shown below: </p><codeblock xml:space="preserve">extern "C" declaration ;
-</codeblock><p>The declaration (or definition) that immediately follows extern
-"C" has the C linkage. </p><codeblock xml:space="preserve">extern "C" {
- declaration ;
- declaration ;
- ...
-}</codeblock><p>Everything between the curly braces has C linkage, unless
-declared otherwise. </p> </section>
-<section id="GUID-88635D46-AEF6-4E8E-969D-D3E56941F289-GENID-1-8-1-11-1-1-5-1-3-1-7-1-4-1-4-1-3-3"> <title>How
-to use extern C</title> <p>While writing header files with C functions
-which will be included by both C and C++ source files, the user must use extern
-"C" properly. See the example below: </p><codeblock xml:space="preserve">/*File: GoodCHeader.h */
-/* Can be used by C/C++ header and source files directly */
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-/* Write C function declarations here */
-void Function1(int, int);
-char* Function3(char*, int);
-int Function2(int);
-#ifdef __cplusplus
-} /* extern "C" */
-#endif
-</codeblock><p>Using <codeph>ifdef __cplusplus</codeph> is required since
-C does not support or recognize the <codeph>extern</codeph> keyword. It is
-C++ that provides the mechanisms for mixing C and C++ codes in the same program.
-To be precise, C++ supports mixing codes that are compiled by C and C++ compatible
-compilers in the same program.</p><p>If the C header is already defined and
-it does not have all the APIs defined under extern "C", then while including
-such a header in C++ source or header files, extern "C" should be used as
-in the example below: </p><codeblock xml:space="preserve">*File: PureCHeader.h */
-/* If C++ header/source files need to include this header, extern "C" should be used*/
-/* Define all C APIs here*/
-void Function1(int, int);
-char* Function3(char*, int);
-int Function2(int);
-#endif
-
-
-//File: CSource.cpp
-// C++ source file using PureCHeader.h
-extern "C" {
-#include "PureCHeader.h"
-}
-void Foo() {
- // use those C APIs here
- int ret = Function2(10);
-}
-</codeblock> </section>
-<section id="GUID-88635D46-AEF6-4E8E-969D-D3E56941F289-GENID-1-8-1-11-1-1-5-1-3-1-7-1-4-1-4-1-3-4"> <title>Mixing
-C and C++ features using extern "C"</title> <p>The developer
-can use all the features of C++ except templates within C by giving those
-functions extern "C" linkage. See the example below:</p><codeblock xml:space="preserve">#include <iostream>
-using namespace std;
-
-extern "C" {
-
-//Can give C linkage to this class!!
-class Sample{
-public:
- Sample(int a = 10) : iMem(a) { }
- void Display() { cout<<"iMem is : "<<iMemend1; }
-private:
- int iMem;
-};
-
-/*
-//Can not give C linkage to template!!
-//If we uncomment this code, then it will give a compilation error.
-template<class DataType> void Foo(DataType data) {
-}*/
-}</codeblock> </section>
-<section id="GUID-9AC33F43-5B75-4994-899F-02CD3CE43E5C"><title>Extending C
-codes with C++ Codes</title><p>Using C linkage, C codes like structures and
-functions that manipulate those structures can be extended efficiently in
-a C++ source file as in the example below: </p><codeblock xml:space="preserve">/* File: CHeader.h */
-typedef struct{
- char* name;
- int id;
- float price;
-} Item;
-
-int Push(Item* item);
-int Pop(Item* item);
-
-
-
-/* File: CppHeader.h */
-//Give external linkage to C structure
-extern "C" {
-# include "CHeader.h"
-}
-
-class MyStack : public Item {
-public:
- MyStack(char* aName, int aId, float aPrice) : name(aName), id(aId), price(aPrice) { }
- int PushOnToStack() { return Push(this);}
- int PopFromStack() { return Pop(this); }
-};
-</codeblock></section>
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License
+"Eclipse Public License v1.0" which accompanies this distribution,
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+ Nokia Corporation - initial contribution.
+Contributors:
+-->
+<!DOCTYPE concept
+ PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-006C503D-1E52-450D-A4DA-8C19B141E09F" xml:lang="en"><title>Introduction
+to Intermixing C and C++</title><shortdesc>When porting an open source application or any C (or C++) applications
+on top of Symbian/S60 using P.I.P.S., the developer will come across situations
+where C and C++ (and Symbian C++ as well) codes will be used together. The
+open source community implements a vast number of libraries that export C
+APIs to the user of such libraries.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<section id="GUID-88635D46-AEF6-4E8E-969D-D3E56941F289-GENID-1-10-1-11-1-1-5-1-3-1-7-1-4-1-4-1-3-1"> <title>When
+and why to use C linkage</title> <p>While porting such applications,
+if developers have to intermix C and C++ code, they then have to depend on
+C++ language features like extern "C" for giving C linkage to some set of
+APIs. This is required because C and C++ compilers handle function prototype
+in a different way. C++ compilers use name mangling, (or name decoration)
+to generate unique names for identifiers in a program. It is because of this
+technique, in C++, that it is possible to overload any functions (this requires
+that all the overloaded functions should have a different argument list).
+The C++ mangled name for any identifier contains all the necessary information
+that may be needed by the linker, such as linkage type, scope, calling convention,
+and others.</p><p>All identifiers (function names or variable names) declared
+or defined in C++ source or headers are subject to name mangling. When it
+comes to C, however, there is nothing called name mangling or overloading.
+It applies when the developer tries to use C APIs by including corresponding
+headers. To avoid name mangling, the developer should mention explicitly that
+those APIs are C APIs, by using the extern "C" keyword. </p> </section>
+<section id="GUID-88635D46-AEF6-4E8E-969D-D3E56941F289-GENID-1-10-1-11-1-1-5-1-3-1-7-1-4-1-4-1-3-2"> <title>Syntax
+of extern C</title> <p>The syntax of extern "C" is shown below: </p><codeblock xml:space="preserve">extern "C" declaration ;
+</codeblock><p>The declaration (or definition) that immediately follows extern
+"C" has the C linkage. </p><codeblock xml:space="preserve">extern "C" {
+ declaration ;
+ declaration ;
+ ...
+}</codeblock><p>Everything between the curly braces has C linkage, unless
+declared otherwise. </p> </section>
+<section id="GUID-88635D46-AEF6-4E8E-969D-D3E56941F289-GENID-1-10-1-11-1-1-5-1-3-1-7-1-4-1-4-1-3-3"> <title>How
+to use extern C</title> <p>While writing header files with C functions
+which will be included by both C and C++ source files, the user must use extern
+"C" properly. See the example below: </p><codeblock xml:space="preserve">/*File: GoodCHeader.h */
+/* Can be used by C/C++ header and source files directly */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+/* Write C function declarations here */
+void Function1(int, int);
+char* Function3(char*, int);
+int Function2(int);
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+</codeblock><p>Using <codeph>ifdef __cplusplus</codeph> is required since
+C does not support or recognize the <codeph>extern</codeph> keyword. It is
+C++ that provides the mechanisms for mixing C and C++ codes in the same program.
+To be precise, C++ supports mixing codes that are compiled by C and C++ compatible
+compilers in the same program.</p><p>If the C header is already defined and
+it does not have all the APIs defined under extern "C", then while including
+such a header in C++ source or header files, extern "C" should be used as
+in the example below: </p><codeblock xml:space="preserve">*File: PureCHeader.h */
+/* If C++ header/source files need to include this header, extern "C" should be used*/
+/* Define all C APIs here*/
+void Function1(int, int);
+char* Function3(char*, int);
+int Function2(int);
+#endif
+
+
+//File: CSource.cpp
+// C++ source file using PureCHeader.h
+extern "C" {
+#include "PureCHeader.h"
+}
+void Foo() {
+ // use those C APIs here
+ int ret = Function2(10);
+}
+</codeblock> </section>
+<section id="GUID-88635D46-AEF6-4E8E-969D-D3E56941F289-GENID-1-10-1-11-1-1-5-1-3-1-7-1-4-1-4-1-3-4"> <title>Mixing
+C and C++ features using extern "C"</title> <p>The developer
+can use all the features of C++ except templates within C by giving those
+functions extern "C" linkage. See the example below:</p><codeblock xml:space="preserve">#include <iostream>
+using namespace std;
+
+extern "C" {
+
+//Can give C linkage to this class!!
+class Sample{
+public:
+ Sample(int a = 10) : iMem(a) { }
+ void Display() { cout<<"iMem is : "<<iMemend1; }
+private:
+ int iMem;
+};
+
+/*
+//Can not give C linkage to template!!
+//If we uncomment this code, then it will give a compilation error.
+template<class DataType> void Foo(DataType data) {
+}*/
+}</codeblock> </section>
+<section id="GUID-9AC33F43-5B75-4994-899F-02CD3CE43E5C"><title>Extending C
+codes with C++ Codes</title><p>Using C linkage, C codes like structures and
+functions that manipulate those structures can be extended efficiently in
+a C++ source file as in the example below: </p><codeblock xml:space="preserve">/* File: CHeader.h */
+typedef struct{
+ char* name;
+ int id;
+ float price;
+} Item;
+
+int Push(Item* item);
+int Pop(Item* item);
+
+
+
+/* File: CppHeader.h */
+//Give external linkage to C structure
+extern "C" {
+# include "CHeader.h"
+}
+
+class MyStack : public Item {
+public:
+ MyStack(char* aName, int aId, float aPrice) : name(aName), id(aId), price(aPrice) { }
+ int PushOnToStack() { return Push(this);}
+ int PopFromStack() { return Pop(this); }
+};
+</codeblock></section>
</conbody></concept>
\ No newline at end of file