c - Error in msgrcv: Invalid Arguments -

-

I am writing a code on a UNIX system in C. I have created a message queue server every time I get a new message I The fork and baby process handles the new customer. The server waits for the new customer here is the code. 

  for (;;) {struct my_msgbuf buf; If (MSGRCV (MScDID, and (BF.M.T.P.), Size (BF), 1, 0) == -1) Peer ("MSGRCV"); If ((pid = fork ()) <0) false ("fork"); If (pid == 0) {// child code}} now code works for the first time, but msgrcv returns the following error on the second visit - msgrcv: invalid instead Argument is waiting for new messages.   
 
 
  MSGRCV  a  msgsz  parameter, but it It is not the size of a  struct my_msgbuf ; rather, it is the number of bytes in the  mtext []  area of ​​the structure. 
 
 You are not really going to use  struct msgbuf , I think it would be normal to define your own with the appropriate place. You have this method, your  Buf  declaration allocates only 1 byte, and then the code tells the kernel that you have  sizeof buf  bytes, which you do not. As a result, the code is called to call  undefined behavior  or UB. 
 
 This can not be understood by  EINVAL , but one must always correct known bugs and retest because UB taints further analysis ...

Comments

Post a Comment

Popular posts from this blog

MySql variables and php -

-
I am getting an error with php in order to format mysql_query () in php to format this string What is the right way? SELECT SELECT SELECT (*) Agents @AgentCount; User_Agent_English, User_Angent_Oursal, US.___Gent_Aginal, COUNT (User_Agent_Percade) ACC, COUNT (*) / (AgentCount) Percentage by agents user_agent_preser order DEC limit limit 50; In PHP, how am i setting $ query $ query = "SELECT count (*) agents @ agentcount; SELECT user_agent_parsed, User_agent_original , COUNT (user_agent_parsed) ascount, COUNT (*) / (@AgentCount) as a percentage by user_agent_parced by URI date DESC limit 50 "; This exact query will work properly if I put it in MySQL directly through a command line session. Do I need to release two separate php calls from mysql_query () and store the results first? I get the following error: There is an error in your SQL syntax; Instead of using a sub-selection and instead of using the 'SELECT user_agent_parsed, user_agent_original, ne...
Read more

url rewriting - How to implement the returnurl like SO in PHP? -

-
This URL should work even after the rewrite. Is this possible? Otherwise, I can only hardcoded everything If you are trying to create a login system with redirection You need to use the HTTP_REFERER header to find out where the user came from so that you can send it back there. The best way to do this is to use something like this in your login form: // - Login php & Lt; Input type = "password" name = "password" /> & Lt; Input type = "hidden" name = "returnrelale" value = "& lt ;? php echo $ redirectURL ;? & gt;" / & Gt; & Lt; / Form & gt; Please note that some ISP, browser or proxy will delete the referrer header, so you can not rely on each user to work fully. If you use a statement, to check whether the header exists or not, you can send those users back to the homepage or whatever. Edit If you are looking to use $ _SERVER ['REQUEST_URI'], if you are running Apache It sho...
Read more

Which Python client library should I use for CouchdB? -

-
I am starting to experiment with CouchDB because it looks like we have the right solution to certain problems That all the work will be on a new project, which does not have any legacy dependency, which the client library will suggest you use, and why? If we overlap any of the OS. Freeband is available only in the collection of its ports, but asks to use the library's project website. None of those people are Ubuntu, which is only with ships, since those two OSAs are not common in libraries, I am probably installing something from source (and hopefully if I have time, then Ubuntu and FreeBSD People pack the package). For those interests, I want to use CouchDB as a convenient intermediate storage space for data passed between different services - think of a message bus system, but less formalities with. For example, we have daemons that download and pars the web page, then send an interesting bit to other daemons for further processing. Many of them are ill-defined until the...
Read more