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sk2:multicast_example
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| Nowa wersja | Poprzednia wersja | ||
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sk2:multicast_example [2016/11/21 22:13] jkonczak utworzono |
sk2:multicast_example [2021/12/20 13:49] (aktualna) jkonczak |
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| ==== Przykład użycia UDP multicast ==== | ==== Przykład użycia UDP multicast ==== | ||
| - | <code cpp multicast_example> | + | <code cpp multicast_example.cpp> |
| + | #include <cstdlib> | ||
| #include <cstdio> | #include <cstdio> | ||
| #include <csignal> | #include <csignal> | ||
| Linia 25: | Linia 26: | ||
| * - bind to some address and MCASTPORT | * - bind to some address and MCASTPORT | ||
| * - prepare ip_mreqn structure – fill it with MCASTIP and optionally (but recommended) with local IP and interface id | * - prepare ip_mreqn structure – fill it with MCASTIP and optionally (but recommended) with local IP and interface id | ||
| - | * - call setsockopt to set option IP_ADD_MEMBERSHIP of the domain IPPROTO_IP to the aforementioned structure | + | * - call setsockopt to set option IP_ADD_MEMBERSHIP on level IPPROTO_IP to the aforementioned structure |
| * - receive datagrams | * - receive datagrams | ||
| * | * | ||
| * setsockopt of IP_ADD_MEMBERSHIP sends an IGMP message "join group" and tells OS that the program waits for messages for the group. | * setsockopt of IP_ADD_MEMBERSHIP sends an IGMP message "join group" and tells OS that the program waits for messages for the group. | ||
| * | * | ||
| - | * More info at: http://www.tldp.org/HOWTO/text/Multicast-HOWTO | + | * More info at: https://tldp.org/HOWTO/Multicast-HOWTO-6.html |
| */ | */ | ||
| Linia 54: | Linia 55: | ||
| // create socket | // create socket | ||
| int sockfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); | int sockfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); | ||
| - | if(sockfd==-1) error(1,errno, "sendto"); | + | if(sockfd==-1) error(1,errno, "socket"); |
| // set SO_REUSEADDR (or only one app will be allowed to receive multicast messages from the groupIP:port pair) | // set SO_REUSEADDR (or only one app will be allowed to receive multicast messages from the groupIP:port pair) | ||
| Linia 115: | Linia 116: | ||
| // close socket AND interrupt all blocked recvfrom | // close socket AND interrupt all blocked recvfrom | ||
| shutdown(sockfd, SHUT_RDWR); | shutdown(sockfd, SHUT_RDWR); | ||
| + | close(sockfd); | ||
| // wait for child | // wait for child | ||
| readerThread.join(); | readerThread.join(); | ||
sk2/multicast_example.1479762787.txt.gz · ostatnio zmienione: 2016/11/21 22:13 przez jkonczak
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