What is an API program and how should it be created?

int hand

hand=handle(this,true)

if hand>0 then

messagebox('Note', 'This program is running', stopsign!)

halt else

open(w_main)

end if

Note: The handle() function does not work in a 32-bit environment due to the call to getmoduleusage() and is only used in .

Method 2: Define an external function:

function ulong findwindowa(ulong classname,string windowname) library ‘

Script: Boolean RTN

ulong l_handle,lu_class

string ls_name

setnull(lu_class)

ls name='api demo' Enter the title of the window

l_handle=findwindowa(lu_class,ls_name)

if l_handle>0 then

halt close

else open(w_main)

end if

APIs are predefined interfaces for programmers to call. is a set of predefined functions for each component of the system. Here's how it works:

1. Before calling the system API in C++, you need to declare the corresponding header file.

Here we use the system function messageboxa, which corresponds to the header file: ".

2. Use angle brackets, compiler.

3. As you can see in the figure in the third part, the messageboxa function contains four parameters. Function parentheses are inside the parameters, and each parameter is separated by a comma. When the mouse is pointed over the function, the function description letter will appear.

4. The null in the parameter is constant.

0, which indicates that it is not set or that it is set by default. It is also possible to write 0 without using constants.

APIs are application programming interfaces, which are predefined functions, or conventions that connect different components of a software system. The purpose is to provide programs and developers with the ability to access a set of routines based on a piece of software or hardware without having to access the source code or understand the details of the inner workings. An API interface belongs to an operating system or program interface, and a GUI interface belongs to a graphical operating system, both of which belong to direct user interfaces.

Sometimes companies use APIs as their public open systems. That is, the company develops its own system interface, p> Zheng Tea.

The Short Friends API (SMS Application Programming Interface) is a set of definitions, programs, and protocols that communicate with each other through the API interface. One of the main functions of the API is to provide a common feature set. Programmers can develop applications by using API functions, which can reduce programming tasks by reducing the need to write useless programs.

The API is also a kind of middleware that provides data sharing for a variety of different platforms.

There are a few things that need to be prepared to open and send your own API:

First: Raise the net high of your API's features.

Second: Set your API access protocol, such as: socket, httpThird: upgrade the authentication method of your API, such as curl, OAuthFourth: find your API development language.

Here's how to write an API program:

Take Windows as an example.

Tools required: C compiler, header and library files, command line window include

int main()

messagebox(null,"hello","world",mb_ok);

return 0;

2. The messagebox function in ** above is to pop up a dialog box. The next step is to compile, here using the command line compilation, first open the command line file, with the suffix cmd or bat.

3. Enter the command [cl source**file name] in the command line. Press the Enter key to execute.

4. After the link is compiled correctly, the executable file is generated, and the executable program is shown in the following figure.

First of all, you must write the API to make it clear what you want to do with it, for example, I want to get the user information from the user system, I wrote an API, the language can be, you can not only write the API and the user system together, the language is in the language used by the user system, and you can use the API simply as a project, and the language is used as you like. The language is determined, and of course it is written with the corresponding instrument.