closeHandle:{[h] .util.logMsg[“Closing handle”]; update handle:0Ni from .cfg.handles where handle=h; @[hclose; h;.util.logError["Error closing handle: ",(string h)]]; }; logMsg:{[x] show string[.z.Z], "-" , x; }; logError:{ logMsg["ERROR: ",x]; :error; };
For some reason the trap is printing error closing handle when infact its closing it. I only want it to print when it might have issue closing it. Am i missing something?
Hi, the trap itself needs to be a function otherwise it will be evaluated regardless of whether the application of your function (hclose) fails or not.
https://code.kx.com/q/ref/apply/#when-e-is-not-a-function
q)logError:{-1"Error: “,x;} q)@[10+;10;logError"Can’t add”] Error: Can’t add 20 q)@[10+;10;{logError"Can’t add"}] 20 q)@[10+;`abc;{logError"Can’t add"}] Error: Can’t add
This looks good but how can i pass a parameter to that function? doesnt seem to allow me to pass anything.
The error thrown is passed as the first parameter to the function. https://code.kx.com/q/ref/apply/#trap. To allow parameters, you need to have a function of rank 2 or greater, you can then create a projection of a rank 1 function by eliding the first parameter:
q)logError:{-1"Error: ",x;} q)@[10+;abc;{logError x,". Couldn't add 10 to ",string y}[;abc]] Error: type. Couldn’t add 10 to abc
You can extend this to allow additional parameters to your error function by creating greater rank functions