Mar 14, 2019 C - Windows - Creating a dynamic-link library (DLL) Submitted by Mi-K on Thursday, March 14, 2019 - 11:08pm Creating a.DLL is an interesting process that allows a better comprehension how a dynamic-link library works on Windows. Jun 18, 2014 I recently learned how to create DLL file in VB.Net - writing the functions in a 'ClassLibrary' template will create a.DLL file. Since in the folder of Source Code, there are many files (C/C Header & Source) I wonder which files should be used.
- How To Create Dll File In C++
- Create Dll In Dev C++
- C++ Add Dll To Project
- How To Create Dll File In Dev C++
- How To Create A Dll
- Dev C++ Create Dll
ofstream
: Stream class to write on filesifstream
: Stream class to read from filesfstream
: Stream class to both read and write from/to files.
These classes are derived directly or indirectly from the classes
istream
and ostream
. We have already used objects whose types were these classes: cin
is an object of class istream
and cout
is an object of class ostream
. Therefore, we have already been using classes that are related to our file streams. And in fact, we can use our file streams the same way we are already used to use cin
and cout
, with the only difference that we have to associate these streams with physical files. Let's see an example:This code creates a file called
example.txt
and inserts a sentence into it in the same way we are used to do with cout
, but using the file stream myfile
instead.But let's go step by step:
Open a file
The first operation generally performed on an object of one of these classes is to associate it to a real file. This procedure is known as to open a file. An open file is represented within a program by a stream (i.e., an object of one of these classes; in the previous example, this wasmyfile
) and any input or output operation performed on this stream object will be applied to the physical file associated to it.In order to open a file with a stream object we use its member function
open
:open (filename, mode);
Where
filename
is a string representing the name of the file to be opened, and mode
is an optional parameter with a combination of the following flags:ios::in | Open for input operations. |
ios::out | Open for output operations. |
ios::binary | Open in binary mode. |
ios::ate | Set the initial position at the end of the file. If this flag is not set, the initial position is the beginning of the file. |
ios::app | All output operations are performed at the end of the file, appending the content to the current content of the file. |
ios::trunc | If the file is opened for output operations and it already existed, its previous content is deleted and replaced by the new one. |
All these flags can be combined using the bitwise operator OR (
|
). For example, if we want to open the file example.bin
in binary mode to add data we could do it by the following call to member function open
:Each of the
open
member functions of classes ofstream
, ifstream
and fstream
has a default mode that is used if the file is opened without a second argument:class | default mode parameter |
---|---|
ofstream | ios::out |
ifstream | ios::in |
fstream | ios::in | ios::out |
For
ifstream
and ofstream
classes, ios::in
and ios::out
are automatically and respectively assumed, even if a mode that does not include them is passed as second argument to the open
member function (the flags are combined).For
fstream
, the default value is only applied if the function is called without specifying any value for the mode parameter. If the function is called with any value in that parameter the default mode is overridden, not combined.File streams opened in binary mode perform input and output operations independently of any format considerations. Non-binary files are known as text files, and some translations may occur due to formatting of some special characters (like newline and carriage return characters).
Since the first task that is performed on a file stream is generally to open a file, these three classes include a constructor that automatically calls the
open
member function and has the exact same parameters as this member. Therefore, we could also have declared the previous myfile
object and conduct the same opening operation in our previous example by writing:Combining object construction and stream opening in a single statement. Both forms to open a file are valid and equivalent.
To check if a file stream was successful opening a file, you can do it by calling to member
is_open
. This member function returns a bool
value of true
in the case that indeed the stream object is associated with an open file, or false
otherwise:Closing a file
When we are finished with our input and output operations on a file we shall close it so that the operating system is notified and its resources become available again. For that, we call the stream's member functionclose
. This member function takes flushes the associated buffers and closes the file:Once this member function is called, the stream object can be re-used to open another file, and the file is available again to be opened by other processes.
In case that an object is destroyed while still associated with an open file, the destructor automatically calls the member function
close
.Text files
Text file streams are those where theios::binary
flag is not included in their opening mode. These files are designed to store text and thus all values that are input or output from/to them can suffer some formatting transformations, which do not necessarily correspond to their literal binary value.Writing operations on text files are performed in the same way we operated with
cout
:Reading from a file can also be performed in the same way that we did with
cin
:This last example reads a text file and prints out its content on the screen. We have created a while loop that reads the file line by line, using getline. The value returned by getline is a reference to the stream object itself, which when evaluated as a boolean expression (as in this while-loop) is
true
if the stream is ready for more operations, and false
if either the end of the file has been reached or if some other error occurred.Checking state flags
The following member functions exist to check for specific states of a stream (all of them return abool
value): bad()
- Returns
true
if a reading or writing operation fails. For example, in the case that we try to write to a file that is not open for writing or if the device where we try to write has no space left. fail()
- Returns
true
in the same cases asbad()
, but also in the case that a format error happens, like when an alphabetical character is extracted when we are trying to read an integer number. eof()
- Returns
true
if a file open for reading has reached the end. good()
- It is the most generic state flag: it returns
false
in the same cases in which calling any of the previous functions would returntrue
. Note thatgood
andbad
are not exact opposites (good
checks more state flags at once).
The member function
clear()
can be used to reset the state flags.get and put stream positioning
All i/o streams objects keep internally -at least- one internal position:ifstream
![Create Create](/uploads/1/3/3/2/133283477/586004074.webp)
![File File](/uploads/1/3/3/2/133283477/798249639.jpg)
istream
, keeps an internal get position with the location of the element to be read in the next input operation.ofstream
, like ostream
, keeps an internal put position with the location where the next element has to be written.Finally,
fstream
, keeps both, the get and the put position, like iostream
.These internal stream positions point to the locations within the stream where the next reading or writing operation is performed. These positions can be observed and modified using the following member functions:
tellg() and tellp()
These two member functions with no parameters return a value of the member typestreampos
, which is a type representing the current get position (in the case of tellg
) or the put position (in the case of tellp
).seekg() and seekp()
These functions allow to change the location of the get and put positions. Both functions are overloaded with two different prototypes. The first form is:seekg ( position );
seekp ( position );
Using this prototype, the stream pointer is changed to the absolute position
position
(counting from the beginning of the file). The type for this parameter is streampos
, which is the same type as returned by functions tellg
and tellp
.The other form for these functions is:
seekg ( offset, direction );
seekp ( offset, direction );
Using this prototype, the get or put position is set to an offset value relative to some specific point determined by the parameter
direction
. offset
is of type streamoff
. And direction
is of type seekdir
, which is an enumerated type that determines the point from where offset is counted from, and that can take any of the following values:ios::beg | offset counted from the beginning of the stream |
ios::cur | offset counted from the current position |
ios::end | offset counted from the end of the stream |
The following example uses the member functions we have just seen to obtain the size of a file:
Notice the type we have used for variables
begin
and end
:streampos
is a specific type used for buffer and file positioning and is the type returned by file.tellg()
. Values of this type can safely be subtracted from other values of the same type, and can also be converted to an integer type large enough to contain the size of the file.These stream positioning functions use two particular types:
streampos
and streamoff
. These types are also defined as member types of the stream class:Type | Member type | Description |
---|---|---|
streampos | ios::pos_type | Defined as fpos<mbstate_t> .It can be converted to/from streamoff and can be added or subtracted values of these types. |
streamoff | ios::off_type | It is an alias of one of the fundamental integral types (such as int or long long ). |
Each of the member types above is an alias of its non-member equivalent (they are the exact same type). It does not matter which one is used. The member types are more generic, because they are the same on all stream objects (even on streams using exotic types of characters), but the non-member types are widely used in existing code for historical reasons.
Binary files
For binary files, reading and writing data with the extraction and insertion operators (<<
and >>
) and functions like getline
is not efficient, since we do not need to format any data and data is likely not formatted in lines.File streams include two member functions specifically designed to read and write binary data sequentially:
write
and read
. The first one (write
) is a member function of ostream
(inherited by ofstream
). And read
is a member function of istream
(inherited by ifstream
). Objects of class fstream
have both. Their prototypes are:write ( memory_block, size );
read ( memory_block, size );
Where
memory_block
is of type char*
(pointer to char
), and represents the address of an array of bytes where the read data elements are stored or from where the data elements to be written are taken. The size
parameter is an integer value that specifies the number of characters to be read or written from/to the memory block.In this example, the entire file is read and stored in a memory block. Let's examine how this is done:
First, the file is open with the
ios::ate
flag, which means that the get pointer will be positioned at the end of the file. This way, when we call to member tellg()
, we will directly obtain the size of the file.Once we have obtained the size of the file, we request the allocation of a memory block large enough to hold the entire file:
Right after that, we proceed to set the get position at the beginning of the file (remember that we opened the file with this pointer at the end), then we read the entire file, and finally close it:
At this point we could operate with the data obtained from the file. But our program simply announces that the content of the file is in memory and then finishes.
Buffers and Synchronization
When we operate with file streams, these are associated to an internal buffer object of typestreambuf
. This buffer object may represent a memory block that acts as an intermediary between the stream and the physical file. For example, with an ofstream
, each time the member function put
(which writes a single character) is called, the character may be inserted in this intermediate buffer instead of being written directly to the physical file with which the stream is associated.The operating system may also define other layers of buffering for reading and writing to files.
When the buffer is flushed, all the data contained in it is written to the physical medium (if it is an output stream). This process is called synchronization and takes place under any of the following circumstances:
- When the file is closed: before closing a file, all buffers that have not yet been flushed are synchronized and all pending data is written or read to the physical medium.
- When the buffer is full: Buffers have a certain size. When the buffer is full it is automatically synchronized.
- Explicitly, with manipulators: When certain manipulators are used on streams, an explicit synchronization takes place. These manipulators are:
flush
andendl
. - Explicitly, with member function sync(): Calling the stream's member function
sync()
causes an immediate synchronization. This function returns anint
value equal to -1 if the stream has no associated buffer or in case of failure. Otherwise (if the stream buffer was successfully synchronized) it returns0
.
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This step-by-step walkthrough shows how to use the Visual Studio IDE to create your own dynamic link library (DLL) written in Microsoft C++ (MSVC). Then it shows how to use the DLL from another C++ app. DLLs (also known as shared libraries in UNIX-based operating systems) are one of the most useful kinds of Windows components. You can use them as a way to share code and resources, and to shrink the size of your apps. DLLs can even make it easier to service and extend your apps.
In this walkthrough, you'll create a DLL that implements some math functions. Then you'll create a console app that uses the functions from the DLL. You'll also get an introduction to some of the programming techniques and conventions used in Windows DLLs.
This walkthrough covers these tasks:
- Create a DLL project in Visual Studio.
- Add exported functions and variables to the DLL.
- Create a console app project in Visual Studio.
- Use the functions and variables imported from the DLL in the console app.
- Run the completed app.
Like a statically linked library, a DLL exports variables, functions, and resources by name. A client app imports the names to use those variables, functions, and resources. Unlike a statically linked library, Windows connects the imports in your app to the exports in a DLL at load time or at run time, instead of connecting them at link time. Windows requires extra information that isn't part of the standard C++ compilation model to make these connections. The MSVC compiler implements some Microsoft-specific extensions to C++ to provide this extra information. We explain these extensions as we go.
This walkthrough creates two Visual Studio solutions; one that builds the DLL, and one that builds the client app. The DLL uses the C calling convention. It can be called from apps written in other programming languages, as long as the platform, calling conventions, and linking conventions match. The client app uses implicit linking, where Windows links the app to the DLL at load-time. This linking lets the app call the DLL-supplied functions just like the functions in a statically linked library.
This walkthrough doesn't cover some common situations. The code doesn't show the use of C++ DLLs by other programming languages. It doesn't show how to create a resource-only DLL, or how to use explicit linking to load DLLs at run-time rather than at load-time. Rest assured, you can use MSVC and Visual Studio to do all these things.
For links to more information about DLLs, see Create C/C++ DLLs in Visual Studio. For more information about implicit linking and explicit linking, see Determine which linking method to use. For information about creating C++ DLLs for use with programming languages that use C-language linkage conventions, see Exporting C++ functions for use in C-language executables. For information about how to create DLLs for use with .NET languages, see Calling DLL Functions from Visual Basic Applications.
Prerequisites
- A computer that runs Microsoft Windows 7 or later versions. We recommend Windows 10 for the best development experience.
- A copy of Visual Studio. For information on how to download and install Visual Studio, see Install Visual Studio. When you run the installer, make sure that the Desktop development with C++ workload is checked. Don't worry if you didn't install this workload when you installed Visual Studio. You can run the installer again and install it now.
- A copy of Visual Studio. For information on how to download and install Visual Studio 2015, see Install Visual Studio 2015. Use a Custom installation to install the C++ compiler and tools, since they're not installed by default.
- An understanding of the basics of using the Visual Studio IDE. If you've used Windows desktop apps before, you can probably keep up. For an introduction, see Visual Studio IDE feature tour.
- An understanding of enough of the fundamentals of the C++ language to follow along. Don't worry, we don't do anything too complicated.
Note
This walkthrough assumes you're using Visual Studio 2017 version 15.9 or later. Some earlier versions of Visual Studio 2017 had defects in the code templates, or used different user interface dialogs. To avoid problems, use the Visual Studio Installer to update Visual Studio 2017 to version 15.9 or later.
Create the DLL project
In this set of tasks, you create a project for your DLL, add code, and build it. To begin, start the Visual Studio IDE, and sign in if you need to. The instructions vary slightly depending on which version of Visual Studio you're using. Make sure you have the correct version selected in the control in the upper left of this page.
To create a DLL project in Visual Studio 2019
- On the menu bar, choose File > New > Project to open the Create a New Project dialog box.
- At the top of the dialog, set Language to C++, set Platform to Windows, and set Project type to Library.
- From the filtered list of project types, select Dynamic-link Library (DLL), and then choose Next.
- In the Configure your new project page, enter MathLibrary in the Project name box to specify a name for the project. Leave the default Location and Solution name values. Set Solution to Create new solution. Uncheck Place solution and project in the same directory if it's checked.
- Choose the Create button to create the project.
When the solution is created, you can see the generated project and source files in the Solution Explorer window in Visual Studio.
To create a DLL project in Visual Studio 2017
- On the menu bar, choose File > New > Project to open the New Project dialog box.
- In the left pane of the New Project dialog box, select Installed > Visual C++ > Windows Desktop. In the center pane, select Dynamic-Link Library (DLL). Enter MathLibrary in the Name box to specify a name for the project. Leave the default Location and Solution name values. Set Solution to Create new solution. Check Create directory for solution if it's unchecked.
- Choose the OK button to create the project.
When the solution is created, you can see the generated project and source files in the Solution Explorer window in Visual Studio.
To create a DLL project in Visual Studio 2015 and older versions
- On the menu bar, choose File > New > Project.
- In the left pane of the New Project dialog box, expand Installed > Templates, and select Visual C++, and then in the center pane, select Win32 Console Application. Enter MathLibrary in the Name edit box to specify a name for the project. Leave the default Location and Solution name values. Set Solution to Create new solution. Check Create directory for solution if it's unchecked.
- Choose the OK button to dismiss the New Project dialog and start the Win32 Application Wizard.
- Choose the Next button. On the Application Settings page, under Application type, select DLL.
- Choose the Finish button to create the project.
When the wizard completes the solution, you can see the generated project and source files in the Solution Explorer window in Visual Studio.
Right now, this DLL doesn't do very much. Next, you'll create a header file to declare the functions your DLL exports, and then add the function definitions to the DLL to make it more useful.
To add a header file to the DLL
- To create a header file for your functions, on the menu bar, choose Project > Add New Item.
- In the Add New Item dialog box, in the left pane, select Visual C++. In the center pane, select Header File (.h). Specify MathLibrary.h as the name for the header file.
- Choose the Add button to generate a blank header file, which is displayed in a new editor window.
- Replace the contents of the header file with this code:
This header file declares some functions to produce a generalized Fibonacci sequence, given two initial values. A call to
fibonacci_init(1, 1)
generates the familiar Fibonacci number sequence.Notice the preprocessor statements at the top of the file. The new project template for a DLL project adds PROJECTNAME_EXPORTS to the defined preprocessor macros. In this example, Visual Studio defines MATHLIBRARY_EXPORTS when your MathLibrary DLL project is built.
How To Create Dll File In C++
When the MATHLIBRARY_EXPORTS macro is defined, the MATHLIBRARY_API macro sets the
__declspec(dllexport)
modifier on the function declarations. This modifier tells the compiler and linker to export a function or variable from the DLL for use by other applications. When MATHLIBRARY_EXPORTS is undefined, for example, when the header file is included by a client application, MATHLIBRARY_API applies the __declspec(dllimport)
modifier to the declarations. This modifier optimizes the import of the function or variable in an application. For more information, see dllexport, dllimport.To add an implementation to the DLL
- In Solution Explorer, right-click on the Source Files node and choose Add > New Item. Create a new .cpp file called MathLibrary.cpp, in the same way that you added a new header file in the previous step.
- In the editor window, select the tab for MathLibrary.cpp if it's already open. If not, in Solution Explorer, double-click MathLibrary.cpp in the Source Files folder of the MathLibrary project to open it.
- In the editor, replace the contents of the MathLibrary.cpp file with the following code:
- In the editor window, select the tab for MathLibrary.cpp if it's already open. If not, in Solution Explorer, double-click MathLibrary.cpp in the Source Files folder of the MathLibrary project to open it.
- In the editor, replace the contents of the MathLibrary.cpp file with the following code:
To verify that everything works so far, compile the dynamic link library. To compile, choose Build > Build Solution on the menu bar. The DLL and related compiler output are placed in a folder called Debug directly below the solution folder. If you create a Release build, the output is placed in a folder called Release. The output should look something like this:
Congratulations, you've created a DLL using Visual Studio! Next, you'll create a client app that uses the functions exported by the DLL.
Create a client app that uses the DLL
When you create a DLL, think about how client apps may use it. To call the functions or access the data exported by a DLL, client source code must have the declarations available at compile time. At link time, the linker requires information to resolve the function calls or data accesses. A DLL supplies this information in an import library, a file that contains information about how to find the functions and data, instead of the actual code. And at run time, the DLL must be available to the client, in a location that the operating system can find.
Whether it's your own or from a third-party, your client app project needs several pieces of information to use a DLL. It needs to find the headers that declare the DLL exports, the import libraries for the linker, and the DLL itself. One solution is to copy all of these files into your client project. For third-party DLLs that are unlikely to change while your client is in development, this method may be the best way to use them. However, when you also build the DLL, it's better to avoid duplication. If you make a local copy of DLL files that are under development, you may accidentally change a header file in one copy but not the other, or use an out-of-date library.
To avoid out-of-sync code, we recommend you set the include path in your client project to include the DLL header files directly from your DLL project. Also, set the library path in your client project to include the DLL import libraries from the DLL project. And finally, copy the built DLL from the DLL project into your client build output directory. This step allows your client app to use the same DLL code you build.
To create a client app in Visual Studio
- On the menu bar, choose File > New > Project to open the Create a new project dialog box.
- At the top of the dialog, set Language to C++, set Platform to Windows, and set Project type to Console.
- From the filtered list of project types, choose Console App then choose Next.
- In the Configure your new project page, enter MathClient in the Project name box to specify a name for the project. Leave the default Location and Solution name values. Set Solution to Create new solution. Uncheck Place solution and project in the same directory if it's checked.
- Choose the Create button to create the client project.
A minimal console application project is created for you. The name for the main source file is the same as the project name that you entered earlier. In this example, it's named MathClient.cpp. You can build it, but it doesn't use your DLL yet.
Create Dll In Dev C++
To create a client app in Visual Studio 2017
- To create a C++ app that uses the DLL that you created, on the menu bar, choose File > New > Project.
- In the left pane of the New Project dialog, select Windows Desktop under Installed > Visual C++. In the center pane, select Windows Console Application. Specify the name for the project, MathClient, in the Name edit box. Leave the default Location and Solution name values. Set Solution to Create new solution. Check Create directory for solution if it's unchecked.
- Choose OK to create the client app project.
A minimal console application project is created for you. The name for the main source file is the same as the project name that you entered earlier. In this example, it's named MathClient.cpp. You can build it, but it doesn't use your DLL yet.
To create a client app in Visual Studio 2015
- To create a C++ app that uses the DLL that you created, on the menu bar, choose File > New > Project.
- In the left pane of the New Project dialog, select Win32 under Installed > Templates > Visual C++. In the center pane, select Win32 Console Application. Specify the name for the project, MathClient, in the Name edit box. Leave the default Location and Solution name values. Set Solution to Create new solution. Check Create directory for solution if it's unchecked.
- Choose the OK button to dismiss the New Project dialog and start the Win32 Application Wizard. On the Overview page of the Win32 Application Wizard dialog box, choose the Next button.
- On the Application Settings page, under Application type, select Console application if it isn't already selected.
- Choose the Finish button to create the project.
When the wizard finishes, a minimal console application project is created for you. The name for the main source file is the same as the project name that you entered earlier. In this example, it's named MathClient.cpp. You can build it, but it doesn't use your DLL yet.
Next, to call the MathLibrary functions in your source code, your project must include the MathLibrary.h file. You could copy this header file into your client app project, then add it to the project as an existing item. This method can be a good choice for third-party libraries. However, if you're working on the code for your DLL and your client at the same time, the header files could get out of sync. To avoid this issue, set the Additional Include Directories path in your project to include the path to the original header.
To add the DLL header to your include path
- Right-click on the MathClient node in Solution Explorer to open the Property Pages dialog.
- In the Configuration drop-down box, select All Configurations if it's not already selected.
- In the left pane, select Configuration Properties > C/C++ > General.
- In the property pane, select the drop-down control next to the Additional Include Directories edit box, and then choose Edit.
- Double-click in the top pane of the Additional Include Directories dialog box to enable an edit control. Or, choose the folder icon to create a new entry.
- In the edit control, specify the path to the location of the MathLibrary.h header file. You can choose the ellipsis (..) control to browse to the correct folder.You can also enter a relative path from your client source files to the folder that contains the DLL header files. If you followed the directions to put your client project in a separate solution from the DLL, the relative path should look like this:
..MathLibraryMathLibrary
Boot camp windows 10 sound on mac mini 2011.If your DLL and client projects are in the same solution, the relative path might look like this:.MathLibrary
When the DLL and client projects are in other folders, adjust the relative path to match. Or, use the ellipsis control to browse for the folder. - After you've entered the path to the header file in the Additional Include Directories dialog box, choose the OK button. In the Property Pages dialog box, choose the OK button to save your changes.
You can now include the MathLibrary.h file and use the functions it declares in your client application. Replace the contents of MathClient.cpp by using this code:
This code can be compiled, but not linked. If you build the client app now, the error list shows several LNK2019 errors. That's because your project is missing some information: You haven't specified that your project has a dependency on the MathLibrary.lib library yet. And, you haven't told the linker how to find the MathLibrary.lib file.
To fix this issue, you could copy the library file directly into your client app project. The linker would find and use it automatically. However, if both the library and the client app are under development, that might lead to changes in one copy that aren't shown in the other. To avoid this issue, you can set the Additional Dependencies property to tell the build system that your project depends on MathLibrary.lib. And, you can set an Additional Library Directories path in your project to include the path to the original library when you link.
To add the DLL import library to your project
- Right-click on the MathClient node in Solution Explorer and choose Properties to open the Property Pages dialog.
- In the Configuration drop-down box, select All Configurations if it's not already selected. It ensures that any property changes apply to both Debug and Release builds.
- In the left pane, select Configuration Properties > Linker > Input. In the property pane, select the drop-down control next to the Additional Dependencies edit box, and then choose Edit.
- In the Additional Dependencies dialog, add MathLibrary.lib to the list in the top edit control.
- Choose OK to go back to the Property Pages dialog box.
- Traktor pro torrent reddit mac. In the left pane, select Configuration Properties > Linker > General. In the property pane, select the drop-down control next to the Additional Library Directories edit box, and then choose Edit.
- Double-click in the top pane of the Additional Library Directories dialog box to enable an edit control. In the edit control, specify the path to the location of the MathLibrary.lib file. By default, it's in a folder called Debug directly under the DLL solution folder. If you create a release build, the file is placed in a folder called Release. You can use the
$(IntDir)
macro so that the linker can find your DLL, no matter which kind of build you create. If you followed the directions to put your client project in a separate solution from the DLL project, the relative path should look like this:..MathLibrary$(IntDir)
If your DLL and client projects are in other locations, adjust the relative path to match. - Once you've entered the path to the library file in the Additional Library Directories dialog box, choose the OK button to go back to the Property Pages dialog box. Choose OK to save the property changes.
Your client app can now compile and link successfully, but it still doesn't have everything it needs to run. When the operating system loads your app, it looks for the MathLibrary DLL. If it can't find the DLL in certain system directories, the environment path, or the local app directory, the load fails. Depending on the operating system, you'll see an error message like this:
C++ Add Dll To Project
One way to avoid this issue is to copy the DLL to the directory that contains your client executable as part of the build process. You can add a Post-Build Event to your project, to add a command that copies the DLL to your build output directory. The command specified here copies the DLL only if it's missing or has changed. It uses macros to copy to and from the Debug or Release locations, based on your build configuration.
To copy the DLL in a post-build event
- Right-click on the MathClient node in Solution Explorer and choose Properties to open the Property Pages dialog.
- In the Configuration drop-down box, select All Configurations if it isn't already selected.
- In the left pane, select Configuration Properties > Build Events > Post-Build Event.
- In the property pane, select the edit control in the Command Line field. If you followed the directions to put your client project in a separate solution from the DLL project, then enter this command:
xcopy /y /d '..MathLibrary$(IntDir)MathLibrary.dll' '$(OutDir)'
If your DLL and client projects are in other directories, change the relative path to the DLL to match. - Choose the OK button to save your changes to the project properties.
How To Create Dll File In Dev C++
Now your client app has everything it needs to build and run. Build the application by choosing Build > Build Solution on the menu bar. The Output window in Visual Studio should have something like the following example depending on your version of Visual Studio:
Congratulations, you've created an application that calls functions in your DLL. Now run your application to see what it does. On the menu bar, choose Debug > Start Without Debugging. Visual Studio opens a command window for the program to run in. The last part of the output should look like:
How To Create A Dll
Press any key to dismiss the command window.
Now that you've created a DLL and a client application, you can experiment. Try setting breakpoints in the code of the client app, and run the app in the debugger. See what happens when you step into a library call. Add other functions to the library, or write another client app that uses your DLL.
Dev C++ Create Dll
When you deploy your app, you must also deploy the DLLs it uses. The simplest way to make the DLLs that you build, or that you include from third parties, available is to put them in the same directory as your app. It's known as app-local deployment. For more information about deployment, see Deployment in Visual C++.