delphi - Local variable broken by closure capture when accessed in nested method -


i've managed reduce problem :

program project1; {$apptype console}  uses   sysutils, threading;  procedure foo(astring: string); var   ltask : itask;   capturedstring : string;   procedure nested;   begin     try       writeln('nested : ' + capturedstring); { ! eintoverflow (win32) here }     except on e : exception       writeln(e.message);       end;    end; begin   capturedstring := astring;   writeln('local : ' + capturedstring);   nested;   ltask := ttask.create(     procedure       procedure anonnested;       begin         writeln(capturedstring); { removing eliminates problem }       end;     begin     end); end;  begin   foo('foo');   readln; end.

here capturedstring variable gets corrupted when accessed within nested method. win32 compile raises eintoverflow, win64 compile writes out (corrupt) empty string - either build can provoked av or other exceptions manipulation in cases reference local variable corrupted when entering nested procedure.

this seems happen if capturedstring captured in closure.

what's going wrong?

this seems compiler bug:

#rsp-18833: capture closure corrupts local variable used in nested method

a workaround use second variable capture in anonymous method:

procedure foo(astring: string); var   ltask : itask;   capturedstring, s2 : string;   procedure nested;   begin     try       writeln('nested : ' + capturedstring);     except on e : exception       writeln(e.message);  { !!! }     end;    end; begin   capturedstring := astring;   s2 := capturedstring;   writeln('local : ' + capturedstring);   nested;   ltask := ttask.create(     procedure       procedure anonnested;       begin         writeln(s2); { capture variable }       end;     begin     end); end;

Comments

Post a Comment

Popular posts from this blog

python Tkinter Capturing keyboard events save as one single string -

is possible store keyboard events 1 string? code below stores 1 char , prints it. card reader or bar code reader, contains collection of character/ string not 1 character @ time. goal save char pressed text variable. from tkinter import * root = tk() def key(event): text= event.char text+= event.char print ("pressed", text) def callback(event): frame.focus_set() print ("clicked at", event.x, event.y) frame = frame(root, width=100, height=100) frame.bind("<key>", key) frame.bind("<button-1>", callback) frame.pack() root.mainloop() currently, creating text variable , everytime key() function gets called, , text stores last character typed. you can define text module level variable , , use module level text inside key function - text = '' def key(event): global text text+= event.char print("pressed", text)
Read more

android - InAppBilling registering BroadcastReceiver in AndroidManifest -

i'm implementing inapp billing in android app. works well, however, i'm trying decouple broadcast receiver activity manifest. suggestion in android's trivialdrive sample: // important: dynamically register broadcast messages updated purchases. // register receiver here instead of <receiver> in manifest // because call getpurchases() @ startup, therefore can ignore // broadcasts sent while app isn't running. // note: registering listener in activity bad idea, done here // because sample. regardless, receiver must registered after // iabhelper setup, before first call getpurchases(). currently there's class extends broadcastreceiver : public class iabbroadcastreceiver extends broadcastreceiver { /** * intent action receiver should filter for. */ public static final string action = "com.android.vending.billing.purchases_updated"; private final iabbroadcastlistener mlistener; public iabbroadcastreceiver(iabbroadcastlistener listener) { m
Read more

javascript - Z-index in d3.js -

i have map , when hover effect on region of map below yellow line , circle, last ones disappear. how can solve problem? http://jsfiddle.net/ot21n9qx/ var arc = g.append("path") .style("fill", "none") .style("stroke", "yellow") .style("stroke-width", 2) .attr("d", "m" + pathorigin[0] + "," + pathorigin[1] + " q" + svgpoint[0] + "," + pathorigin[1] + " " + svgpoint[0] + "," + svgpoint[1]); var circlesize = d3.scale.linear() .domain([0, 0.5, 1]) .range([4, 10, 4]); svg not have z order draws objects in order created. need create path , circle after create highlight regions. here forked fiddle: http://jsfiddle.net/o00fzgaf/1/
Read more