Pcall is a function which catches an error and returns it . For example, if you had a function like
local function add(x, y) if math.random(1, 2) == 1 then error("adding failed") end return x + y end
then you'd use a pcall. An actual use for this would be for things like datastores and http requests, since most, if not everything internet-based has a chance to fail. However, if we took the function above and someone wanted to pcall it, most people would just go and do something like this.
local success, value while not success do success, value = pcall(function() return add(1, 1) end) end print(value)
or just pcall it once like
pcall(function() print(add(1, 1)) end)
However, you create a new function to call these other functions! Every function in Lua, built in or not, can be called the same way and there's no special way you need to call it like only using the above. To solve this problem, you can just do
pcall(add, 1, 1)
so that you don't need to create a whole new function. In case you didn't know, you can specify the parameters to pass into the function after you specify the function.
Now, you might be asking how to apply this to a Roblox function. You can't just do
In order to solve this, you'll need to understand that
function foo:bar(x) print(self, x) end
is the same as
function foo.bar(self, x) print(self, x) end
is the same as
With this knowledge, we can just do
pcall(game:GetService("HttpService").GetAsync, game:GetService("HttpService"), "example.com")
Since people usually use pcalls for datastores, I'll use that for the next part.
What if the pcall fails, though? The pcall would be useless. To fix this, you need to just retry the request. However, assuming it's an error from you exceeding the call limitations, you'll need to wait in between like
local datastore = game:GetService("DataStoreService"):GetGlobalDataStore() local success = pcall(datastore.SetAsync, datastore, "foo") while not success do wait(10) --You should not use this unless the thing you are checking for does not have an event when it changes. if game:GetService("DataStoreService"):GetRequestBudgetForRequestType(Enum.DataStoreRequestType.SetIncrementAsync) > 0 then success = pcall(datastore.SetAsync, datastore, "foo") end end
Now your pcalled code won't have a random chance of breaking everything else.