I can't get yield functions to work

Questions & Answers
1

Hello I place a sprite prefab on my game with left click and I try to stop any others actions until the mouse button is released. Otherwise many instances of this prefab are created and I only want one.

I tried to create a coroutine to wait until the left button is released but its not working. And even if I replace it by a WaitForSeconds() function I got no delay at all in both case.

Here is my Code:

IEnumerator WaitForButtonUp ( )
	{
    //do
    //	{
    //    yield return null;
    //	} 
	//while ( Input.GetMouseButtonUp(0) );
	yield return new WaitForSeconds(8.0f);

	}	

void StartToWait() {
        print("Starting " + Time.time);
        StartCoroutine(WaitForButtonUp());
        print("Before WaitForButtonUp Finishes " + Time.time);
    }

No delay are shown in console :

Starting 6.619012

Before WaitForButtonUp Finishes 6.619012

2

The problem is that StartToWait does not yield for WaitForButtonUp to complete. It asks the coroutine to start and continue to the next print statement. Meanwhile, the coroutine execute - and yield - correctly. Just place the statement within the coroutine to verify.

AFAIK, there’s no way to have a void method yield. A coroutine may yield a second coroutine, though:

IEnumerator StartToWait()
{
	Debug.Log("StartToWait BEFORE " + Time.time);
	yield return StartCoroutine(WaitForButtonUp());
	Debug.Log("StartToWait AFTER " + Time.time);
}

IEnumerator WaitForButtonUp()
{
	Debug.Log("WaitForButtonUp BEFORE " + Time.time);
	yield return new WaitForSeconds(8.0f);
	Debug.Log("WaitForButtonUp AFTER " + Time.time);
}
3

At the light of your comment I found a working a solution for my problem wich is holding a script until a condition is meet.
In my case wait until the mouse button is released before i can execute my drawing script again.
I can’t really hold it because the coroutine is executed in parallel but I can disable it until the coroutine have finish the yield using a simple bool variable.

Here is my working code :

IEnumerator WaitForButtonUp()
        {
	//disable the desired script here
	cantClick=true;	

        do
   	{
           yield return null;
        } 
        while ( !Input.GetMouseButtonUp(0) );
	
	//enable it here
	cantClick=false;	
    
	}

And the script I want to disable looks like this :

void DrawItems()
{

	if (Input.GetMouseButton(0))
		{
		if (!LevelData.dataTilesLayer[boardX,boardY] & !cantClick)
			{
			// Place Mob
			PlaceItem();
            StartCoroutine("WaitForButtonUp"); //WAIT IN PARALLEL FOR MOUSE UP
			
			}
        }
  }

Thanks again for your input.