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PORun multiple process server before client
 

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    <p>I am still working on the same homework of Operating System course. Now , here is my question (Firstly, I am rewriting the HW's content): Two programs will be implemented : a client program "get" and a server program called "iserv". A client will ask the server to retrieve and sent all integers in a certain range. The server will be a multi-process program. It will create child processes to handle requests coming from clients. POSIX message queues will be used. Here my iserv.c (server program)</p> <pre><code>struct item /*struct for client requests to the server*/ { int maxvalue; int minvalue; char *queuename; }; int main(int argc , char *argv[]) { pid_t apid1; FILE *fp; mqd_t mq; const char *msgqueue = "/serverqueue"; int oflag = (O_RDWR|O_CREAT); mode_t mode = (S_IRUSR|S_IWUSR); if(argc != 3) { printf("wrong number of arguments"); exit(1); } //create server message queue mq = mq_open(msgqueue ,oflag , mode , NULL); if(mq==-1) { perror("can not open msg queue\n"); exit(1); } printf("mq opened , mq id = %d\n" , (int) mq); //******get the maxvalue and minvalue******* mq_getattr(mq , &amp;attr); printf("mq maximum msgsize = %d\n" , (int) attr.mq_msgsize); /*allocate large enough space for the buffer*/ buflen = attr.mq_msgsize; bufptr = (char *)malloc(buflen); n = mq_receive(mq , (char *)bufptr , buflen , NULL); if(n == -1) { perror("mq_receive failed\n"); exit(1); } itemptr = (struct item *) bufptr; printf("min value = %d\n" , itemptr-&gt;minvalue); printf("max value = %d\n" , itemptr-&gt;maxvalue); fprintf(stderr , "queue name = %s\n" , itemptr-&gt;queuename); free(bufptr); mq_close(mq); mq_unlink(msgqueue); return 0; } </code></pre> <p>and get.c(client program)</p> <pre><code>struct item /*struct for client requests to the server*/ { int maxvalue; int minvalue; char *queuename; }; int main(int argc , char *argv[]) { FILE *file; mqd_t mq; mqd_t mq2; const char *msgqueue = "/serverqueue"; int oflag = (O_RDWR|O_CREAT); mode_t mode = (S_IRUSR|S_IWUSR); struct mq_attr *attr = NULL; struct item item; //for serverqueue int n; if(argc != 5) { printf("wrong number of arguments"); exit(1); mq = mq_open(msgqueue ,oflag , mode , attr); if(mq==-1) { perror("can not open msg queue\n"); exit(1); } printf("mq opened , mq id = %d\n" , (int) mq); //send max - min values and the client message queue name to the serverqueue as a request while(1) { item.maxvalue = atoi(argv[3]); item.minvalue = atoi(argv[2]); item.queuename = clientqueue; n = mq_send(mq , (char *) &amp;item , sizeof(item) , 0); if(n==-1) { perror("mq_send failed\n"); exit(1); } else { printf("mq_send success , item size = %d\n" , sizeof(struct item)); printf("%d" , item.maxvalue); printf("%d" , item.minvalue); printf("\n" , item.queuename); } } mq_close(mq); mq_unlink(msgqueue); return 0; } </code></pre> <p>Makefile:</p> <pre><code>all: iserv get iserv: iserv.c gcc -g -Wall -o iserv iserv.c -lrt get: get.c gcc -g -Wall -o get get.c -lrt clean: rm -fr *o iserv get </code></pre> <p>Now , my first question is even if I remove the message queue by using mq_close and mq_unlink , when I want to run these two programs terminal says that : nothing do be done for 'all'. I need to remove something else to rerun these two programs without closing or deleting anything with hand. What is this??</p> <p>Second question is that <code>char *queuename;</code> in the message response cannot be taken by the server as a name. It prints out something silly on the terminal , how can I pass the string queuename to the server in this message response??</p> <p>Please help me , homework due date is close I need to solve these problems , thank you for all help !!</p>
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    1. USJonathon Reinhart
    1. USBegumm
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    1. CO\`backticks\` are for inline `code`. Indent four spaces for code blocks (that's what the **{ }** code button does).
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      1. USJonathon Reinhart
    2. COThank you for fixing me . Now I need an answer to my questions:)
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      1. USBegumm
    3. CO"nothing to do for all" sounds like `make` telling you nothing changed so there is nothing to rebuild. What's your second question?
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      1. USDuck
 

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