… is user for unidirectional inter process communication on a single machine.<\/p>\n
In the following example a pipe gets created for a communication from the child to the parent.<\/p>\n
Source code<\/strong><\/p>\n Output<\/strong><\/p>\n File descriptors<\/strong><\/p>\n … is user for unidirectional inter process communication on a single machine. In the following example a pipe gets created<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"inline_featured_image":false},"categories":[65],"tags":[],"_links":{"self":[{"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/posts\/7285"}],"collection":[{"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7285"}],"version-history":[{"count":1,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/posts\/7285\/revisions"}],"predecessor-version":[{"id":16797,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=\/wp\/v2\/posts\/7285\/revisions\/16797"}],"wp:attachment":[{"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7285"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7285"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.max-sperling.bplaced.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7285"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}\r\n#include <sys\/types.h>\r\n#include <unistd.h>\r\n#include <cstring>\r\n#include <iostream>\r\n\r\nint main()\r\n{\r\n int pipefd[2]; \/\/ pipefd[0] ... read, pipefd[1] ... write\r\n pipe(pipefd);\r\n pid_t pid = fork();\r\n\r\n if (pid == -1)\r\n {\r\n \/* Couldn't fork *\/\r\n std::cout << "Couldn't fork" << std::endl;\r\n }\r\n else if (pid == 0)\r\n {\r\n \/* Child process *\/\r\n close(pipefd[0]); \/\/ close read end\r\n dup2(pipefd[1], 1); \/\/ redirect write end to stdout\r\n close(pipefd[1]); \/\/ close origin write end\r\n execlp(".\/child.out", "child.out", NULL ); \/\/ returns only in error case\r\n std::cout << "Exec failed with: " << errno << std::endl;\r\n }\r\n else\r\n {\r\n \/* Parent process *\/\r\n close(pipefd[1]); \/\/ close write end\r\n char buf[1024];\r\n while (read(pipefd[0], buf, sizeof(buf)) > 0)\r\n {\r\n std::cout << "My child said: " << buf << std::endl;\r\n memset(buf, 0, sizeof(buf));\r\n }\r\n close(pipefd[0]); \/\/ close unecessary read end\r\n }\r\n\r\n return 0;\r\n}\r\n<\/pre>\n\r\n#include <unistd.h>\r\n#include <iostream>\r\n\r\nint main()\r\n{\r\n std::cout << "Hold" << std::endl;\r\n sleep(1);\r\n std::cout << "my" << std::endl;\r\n sleep(1);\r\n std::cout << "beer" << std::endl;\r\n\r\n return 0;\r\n}\r\n<\/pre>\n\r\n$ .\/main.out \r\nMy child said: Hold\r\n\r\nMy child said: my\r\n\r\nMy child said: beer\r\n\r\n<\/pre>\n
\r\n Parent | Child \r\n---------------------------------------\r\n 0 stdin | 0 stdin \r\n 1 stdout | 1 pipefd[1]\r\n 3 stderr | 2 pipefd[1]\r\n ... | ...\r\n X pipefd[0] |\r\n ... |\r\n---------------------------------------\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"