c - Shared Memory and semaphores for (multiple) client and server game -


i have program little game course in c , has done using shared-memory, semaphores , client/server architecture can handle multiple clients (the exact requirement game 2).

the 2 clients need turns in turns , represented same program (no fork() involved here - both started ./client)

the server has create resources when starts up. main problem regarding semaphores. (the shared memory , game-logic stuff works or isn't difficult implement.)

to decide if server or client has access shared-memory need 1 semaphore. need second 1 decide of clients has access. right?

so got hint done assigning ids clients. shared-memory has 3 additional variables so:

struct game {     int id_needed, client_id, id_ready;     ... // additional stuff needed game logic };

as server boots i'm initializing 1 semaphore 0 , other 1 1. when first client appears checks if id still 0 (it's initialized zero)

if so, tries this:

while(my_id == 0) {    if(semaphore_down(semaphore_1) == 0) // check if have access shared mem    {        shared_memory->id_needed = 1;        if(shared_memory->id_ready == 1)        {            my_id = shared_memory->client_id;            (void) printf("debugging: id %d\n", my_id);        }    } } shared_memory->id_needed = 0;

and in server ...

while(1) {     if(shared_memory->id_needed = 1)     {         (void) printf("debugging: id needed client!");         shared_memory->client_id++;         shared_memory->id_ready = 1;         (void) printf("debbuging: dispatched new id: %d", shared_memory->client_id);     }     // if enough players, start game ... }

i'm stuck here. server increments id (which logical), i'm stuck resolve problem.

i want clients work alternately on shared-memory , server check values of game etc.

i've never worked semaphores before , documentation or examples find work 1 client , 1 server, never multiple clients.

please enlighten me!

i see 1 strange thing , 2 things mistakes here

  1. i see semaphore_down no semaphore_up in code showed
  2. you assign instead of comparing: if(shared_memory->id_needed = 1)
  3. even if comparison, not right anyway since compiler free optimize out. make variable volatile hint compiler variable can change outside of serial code flow. or better declare atomic.

Comments

Post a Comment

Popular posts from this blog

commonjs - How to write a typescript definition file for a node module that exports a function? -

consider, toml node module can use: // toml.d.ts declare module toml { export function parse(value:string):any; } declare module "toml" { export = toml; } then: /// <reference path="../../../../../defs/toml/toml.d.ts"/> import toml = require('toml'); toml.parse(...); however, node module export single function, such 'glob' ( https://github.com/isaacs/node-glob ). the node usage of module be: var glob = require("glob") glob("*.js", {}, callback(err, files) { ... }); you'd naively expect this: // glob.d.ts declare function globs(paths:string, options:any, callback:{(err:any, files:string[]):void; ...but because typescripts 'import' semantics bit strange, seems can use 'import .. = require()' statement alias modules . trying call: /// <reference path="../../../../../defs/glob/glob.d.ts"/> import blog = require('glob'); results in: error ts2072: mod
Read more

openid - Okta: Failed to get authorization code through API call -

i'm integrating okta own idp server using okta's api. i'm implementing authorization code flow following steps below: in own server, use /api/v1/authn endpoint sessiontoken. use sessiontoken obtain authorization calling endpoint: /oauth2/v1/authorize?client_id=" + clientid + "&sessiontoken=" + sessiontoken + "&response_type=code&response_mode=query&scope=openid&redirect_uri=" + redirecturl + "&state=evanyang&nonce=" it's supposed return response status code 302 , location header containing redirect url code value. however, keep getting response status code 200 , without location header, html body saying "you using unsupported browser." , "javascript disabled on browser." according api documentation: http://developer.okta.com/docs/api/resources/oidc.html#authentication-request , sessiontoken parameter sufficient this: an okta one-time sessiontoken. allows api-based
Read more

thorough guide for profiling racket code -

did googling ("racket profiling", "racket measure performance"), didn't find , there no examples in docs. did google "profile" search on htdp - no luck. (profile (f ...)) output isn't obvious other small snippets. ideally want python's python -m cprofile usage examples. when search "python profiling", both duckduckgo , google give top result: 26.4. python profilers . (although scanned quickly, seems more of reference "thorough usage guide" examples. if had else in mind, perhaps please link that?) the equivalent racket documentation be: profile: statistical profiler . a usage example: #lang racket (require profile) (profile-thunk (thunk (function-to-profile arg0 arg1) )) here (thunk e) convenience (lambda () e) . bigger example: #lang racket (module mod racket (provide f) (define (f) (for/list ([i 10000]) i))) (require (prefix-in mod: 'mod)) (define (f) (for ([i 10000
Read more