## IupHelp

Opens the given URL. In UNIX executes Netscape, Safari (MacOS) or Firefox (in Linux) passing the desired URL as a parameter. In Windows executes the shell "open" operation on the given URL.

In UNIX you can change the used browser setting the environment variable IUP_HELPAPP or using the global attribute "HELPAPP".

It is a non synchronous operation, i.e. the function will return just after execute the command and it will not wait for its result.

Since IUP 3.17, it will use the IupExecute function.

### Parameters/Return

    int IupHelp(const char* url); [in C]
    iup.Help(url: string) -> (ret: number) [in Lua]

url: may be any kind of address accepted by the Browser, that is, it can include 'http://', or be just a file name, etc.

Returns: 1 if successful, -1 if failed. In Windows can return -2 if file not found.