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Mar 6, 2014 · First off, you need C++, not C. C is not an object-oriented language, and it doesn't have standard libraries for things like queues. For C++, look for the std::queue. std::queue q; /// etc; You can, of course, make queue-like structure in C, but you'll wind up doing a lot of the work yourself.
Jun 17, 2010 · The following is a simple example of a server that receives messages from clients until it receives an "exit" message telling it to stop. The code for the server: mqd_t mq; struct mq_attr attr; char buffer[MAX_SIZE + 1]; int must_stop = 0; /* initialize the queue attributes */. attr.mq_flags = 0; attr.mq_maxmsg = 10;
Jul 3, 2018 · To copy a string use strcpy: strcpy(ptr->data, x); Or since you have a limited array, maybe use strncpy: strncpy(ptr->data, x, sizeof(ptr->data) - 1); ptr->data[sizeof(ptr->data) - 1] = '\0'; For strncpy it will not add the terminating '\0' character if the source is equal or longer than the specified length, so we have to make sure that the ...
@Raymond Hopefully you understand that queue_node is a container. It holds two things: the data element you're queuing, and a pointer to the next queue_node (or null if its the last node in the queue).
Jan 2, 2011 · * * @param queue Pointer to the queue that should be initialized * @return 0 on success see pthread_mutex_init */ int thread_queue_init(struct threadqueue *queue); /** * Adds a message to a queue * * @ingroup ThreadQueue * * thread_queue_add adds a "message" to the specified queue, a message * is just a pointer to a anything of the users choice.
Apr 3, 2013 · Note, the foreach approach doesn't work if you need to add any items to the queue as you are processing the queue (e.g. if you are implementing BFS algorithm) because then the enumerator would be invalidated.
In C, a string is a char *, which is a pointer to a sequence of contiguous char values ending in a \0. If you want to store strings, your elements array should be a char **, which is a pointer to a pointer to char. This is the normal way in C to refer to dynamically allocated array of pointers. /* Allocate an array of 10 "char *" values.
While std::queue<int>().swap(q) is equivalent to the code above, q = std::queue<int>() need not be equivalent. . Since there is no transfer of ownership in the assignment of the allocated memory some containers (like vector) might just call the destructors of the previously held elements and set the size (or equivalent operation with the stored pointers) without actually releasing the mem
Oct 12, 2018 · With C89 you can make a message queue based on linked lists. A simple message queue will probably be enough for the OP. Other than that, you can implement OS structures like semaphores using assembly functions so you get locks/mutexes if that's not already supported by the compiler the OP is currently using.
Apr 28, 2017 · C has very little in terms of data structures and forces you to resort to arguable tricks to implement abstract data types: see an article titled “Incomplete types as abstractions” if you can find it, or see how the principles are applied in, say, PolarSSL's bignum.h file. C++ on the other hand is supposed to allow you to do pretty much everything you can do in C and give you ways to implement abstract data structures.
