Plugin not accepting non-static char arrays?

SDKs Plugins
1

I’m trying to create a plugin to create an inspector properties drop-down menu from a char array.

I can do this with a static array. For example:

const char* charArray[] {
"a",
"b",
"c",
"d",
"e"
};

static REALproperty VectorProperties[] = {
	{"New Image", "VectorImage", "Integer", REALpropInvalidate, NULL, NULL,  0, nil, sizeof(charArray) / sizeof(charArray[0]), charArray}

Will give me a drop down menu containing the array values.

However trying to insert values into a globally defined non-static array inside the plugin constructer method crashes Xojo on load but is working in debugger. For example: (same properties method)

//inserting "0, 1, 2, 3, 4" into an array

const char* charArray[5];

static void VectorConstructor(REALcontrolInstance control)
{
	for (int i = 0; i < 5; i++) {
		string newNumString = "";
		const char* newNumChar = "";
		newNumString = to_string(i);
		newNumChar = newNumString.c_str();
		charArray[i] = newNumChar;
	}

Can Xojo/Xojo plugins not accept arrays that are non-static? Is there something i’m missing?

Thanks.

2

First it looks like you make a definition of the property with a list of enum labels. Looks fine.

But the code there is strange.
Since you use std::string there, the ptr you get from c_str() function is temporary. putting it in charArray[] won’t be good, since on access later it will point to released string.

Maybe you think again what you want to do?

3

Okay that’s understandable, but for example lets just make a very simple for loop to insert a char containing “abc” into the array like this:

const char* charArray[5];
const char* newChar = "abc";

static void VectorConstructor(REALcontrolInstance control) {
	for (int i = 0; i < 5; i++) {
		charArray[i] = newChar;
	}
}

This causes Xojo to crash on load. All variables are globally defined? So what is making this plugin fail?

4

I’m trying to create a drop-down menu property of a class containing file names from a specified folder.
The properties definition requires a const char* and the file names are returned as a stringstream hence the example of code before containing the data type conversions.
As you pointed out my current method won’t work, is there a better way of doing this conversion to work with what i’m trying to accomplish?

5

You would have to new some memory area for it with malloc or new operator and let it persist over the lifetime of the whole plugin.

6

Crash log?
Do you know what line crashes exactly?

7

Code compiles fine into dll file through visual studio, but no crash log as it’s failing when Xojo is loading in plugins. As far as i know Xojo doesn’t create crash logs during load time.

I suspect that Björn may be correct and i have been testing solutions with malloc memory allocation, but am yet to have a working project.

8

You say the plugin defines a drop-down menu in the inspector properties pane of the IDE. That is only possible with a static array. Usually this is being done for a REALcontrol. Any other way other than a static array will crash Xojo. Our plugins use these static arrays in many cases to ease the setup of a plugin for runtime purposes.

1 Like
9

That’s exactly the answer i was looking for, Alfred. Thank you very much