c++ - Calculate some values using template size_t param -

-

this question has answer here:

what c++ way calculate values using template params?

template<typename t, size_t size> class threadsafearray { private:     static const size_t block_size = size > 32 ? 16 : 4;     static const size_t mutex_count = size / block_size + 1;     ... };

or this

template<typename t, size_t size> class threadsafearray { private:     enum     {         block_size = size > 32 ? 16 : 4,         mutex_count = size / block_size + 1     };         .... };

or somehow else?

the enum hack old way provide compile-time computations. used when in class initialization not supportted compilers, static const cannot used. nowadays fixed in modern compilers. preferred way use static const.

check this answer more info.


Comments

Post a Comment

Popular posts from this blog

wireshark - USB mapping with python -

-
while reading ctf write-ups came across script #!/usr/bin/env python import struct import image import dpkt init_x, init_y = 100, 400 def print_map(pcap, device): picture = image.new("rgb", (1200, 500), "white") pixels = picture.load() x, y = init_x, init_y ts, buf in pcap: device_id, = struct.unpack("b", buf[0x0b]) if device_id != device: continue data = struct.unpack("bbbb", buf[-4:]) status = data[0] x = x + data[1] y = y + data[2] if (status == 1): in range(-5, 5): j in range(-5, 5): pixels[x + , y + j] = (0, 0, 0, 0) else: pixels[x, y] = (255, 0, 0, 0) picture.save("riverside-map.png", "png") if __name__ == "__main__": f = open("usb.pcap", "rb") pcap = dpkt.pcap.reader(f) print_map(pcap, 5) f.close() and ...
Read more

c++ - nodejs socket.io closes connection before upgrading to websocket -

-
i'm trying write c++ client talk websocket server written using nodejs , socket.io. can't c++ client establish websocket connection; server drops connection right after client requests http connection upgraded websocket. i used tcpdump watch packets going , forth. when use websocket server browser, works great , tcpdump output shows packets going , forth. when try connect server using c++ client, websocket connection never gets established. output tcpdump shows upgrade request being sent server followed server dropping connection. i tried replicating sequence of events using nc . connected server (running on port 8080) , copy-pasted exact set of headers sent browser, captured tcpdump. duplicate of working headers, connection dropped. there no output on server end indicating why connection gets dropped. here headers sent: get /socket.io/?type=player&eio=3&transport=websocket&sid=7mdclht_8ctsd6f4aaac http/1.1 host: localhost:8080 connection: upgrade prag...
Read more

Deploying Qt Application on Android is really slow? -

-
as may know there 3 ways deploy qt application on android : use ministro service install qt deploy local qt libraries temporary directory bundle qt libraries in apk the first method takes 30 seconds , needs install apk . ministro . second takes 1 minute me ! , anytime try run program qt creator pushes qt libraries device. third 1 makes .apk file big , again takes 1 minute me. think situation that's not reasonable develop android application using qt. there way make deploying process faster? almost full year since op , things have not changed @ all. deployment of 7 mb apk takes on minute , half project compiles in 5 seconds. reason answering not problem got resolved, offer alternative solution. i've implemented "workaround" consisting of 2 applications work in tandem - 1 on pc , 1 on device - created compile files remotely, turned out faster alternative deployment well. on host create application launches compilation in separate process, when do...
Read more