{"id":7024,"date":"2022-12-20T19:34:40","date_gmt":"2022-12-20T22:34:40","guid":{"rendered":"http:\/\/lode.uno\/linux-man\/index.php\/2022\/12\/20\/tcl_detachpids-man3\/"},"modified":"2022-12-20T19:34:40","modified_gmt":"2022-12-20T22:34:40","slug":"tcl_detachpids-man3","status":"publish","type":"post","link":"https:\/\/lode.uno\/linux-man\/2022\/12\/20\/tcl_detachpids-man3\/","title":{"rendered":"Tcl_DetachPids (man3)"},"content":{"rendered":"

Tcl_DetachPids<\/h1>\n

NAME<\/a>
SYNOPSIS<\/a>
ARGUMENTS<\/a>
DESCRIPTION<\/a>
KEYWORDS<\/a> <\/p>\n

\n

______________________________________________________________________________<\/p>\n

NAME <\/a> <\/h2>\n

Tcl_DetachPids, Tcl_ReapDetachedProcs, Tcl_WaitPid \u2212 manage child processes in background<\/p>\n

SYNOPSIS <\/a> <\/h2>\n

#include <\/b><\/p>\n

Tcl_DetachPids<\/b>(numPids, pidPtr<\/i>)<\/p>\n

Tcl_ReapDetachedProcs<\/b>()<\/p>\n

Tcl_Pid
Tcl_WaitPid<\/b>(pid, statusPtr, options<\/i>)<\/p>\n

ARGUMENTS <\/a> <\/h2>\n\n\n\n\n\n\n
<\/td>\n\n

int numPids<\/i> (in)<\/p>\n<\/td>\n

<\/td>\n\n

Number of process ids contained in the array pointed to by pidPtr<\/i>.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

int *pidPtr<\/i> (in)<\/p>\n<\/td>\n

<\/td>\n\n

Address of array containing numPids<\/i> process ids.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

Tcl_Pid pid<\/i> (in)<\/p>\n<\/td>\n

<\/td>\n\n

The id of the process (pipe) to wait for.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

int *statusPtr<\/i> (out)<\/p>\n<\/td>\n

<\/td>\n\n

The result of waiting on a process (pipe). Either 0 or ECHILD.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

int options<\/i> (in)<\/p>\n<\/td>\n

<\/td>\n\n

The options controlling the wait. WNOHANG specifies not to wait when checking the process.<\/p>\n<\/td>\n<\/tr>\n<\/table>\n

______________________________________________________________________________<\/p>\n

DESCRIPTION <\/a> <\/h2>\n

Tcl_DetachPids<\/b> and Tcl_ReapDetachedProcs<\/b> provide a mechanism for managing subprocesses that are running in background. These procedures are needed because the parent of a process must eventually invoke the waitpid<\/b> kernel call (or one of a few other similar kernel calls) to wait for the child to exit. Until the parent waits for the child, the child\u2019s state cannot be completely reclaimed by the system. If a parent continually creates children and doesn\u2019t wait on them, the system\u2019s process table will eventually overflow, even if all the children have exited.<\/p>\n

Tcl_DetachPids<\/b> may be called to ask Tcl to take responsibility for one or more processes whose process ids are contained in the pidPtr<\/i> array passed as argument. The caller presumably has started these processes running in background and does not want to have to deal with them again.<\/p>\n

Tcl_ReapDetachedProcs<\/b> invokes the waitpid<\/b> kernel call on each of the background processes so that its state can be cleaned up if it has exited. If the process has not exited yet, Tcl_ReapDetachedProcs<\/b> does not wait for it to exit; it will check again the next time it is invoked. Tcl automatically calls Tcl_ReapDetachedProcs<\/b> each time the exec<\/b> command is executed, so in most cases it is not necessary for any code outside of Tcl to invoke Tcl_ReapDetachedProcs<\/b>. However, if you call Tcl_DetachPids<\/b> in situations where the exec<\/b> command may never get executed, you may wish to call Tcl_ReapDetachedProcs<\/b> from time to time so that background processes can be cleaned up.<\/p>\n

Tcl_WaitPid<\/b> is a thin wrapper around the facilities provided by the operating system to wait on the end of a spawned process and to check a whether spawned process is still running. It is used by Tcl_ReapDetachedProcs<\/b> and the channel system to portably access the operating system.<\/p>\n

KEYWORDS <\/a> <\/h2>\n

background, child, detach, process, wait<\/p>\n

\n","protected":false},"excerpt":{"rendered":"

Tcl_DetachPids, Tcl_ReapDetachedProcs, Tcl_WaitPid \u2212 manage child processes in background <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2536],"tags":[2538,3007,3374],"class_list":["post-7024","post","type-post","status-publish","format-standard","hentry","category-3-llamadas-de-bibliotecas","tag-2538","tag-man3","tag-tcl_reapdetachedprocs"],"gutentor_comment":0,"_links":{"self":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/7024","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/comments?post=7024"}],"version-history":[{"count":0,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/7024\/revisions"}],"wp:attachment":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/media?parent=7024"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/categories?post=7024"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/tags?post=7024"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}