{"id":7171,"date":"2022-12-20T19:35:43","date_gmt":"2022-12-20T22:35:43","guid":{"rendered":"http:\/\/lode.uno\/linux-man\/index.php\/2022\/12\/20\/tcl_createfilehandler-man3-2\/"},"modified":"2022-12-20T19:35:43","modified_gmt":"2022-12-20T22:35:43","slug":"tcl_createfilehandler-man3-2","status":"publish","type":"post","link":"https:\/\/lode.uno\/linux-man\/2022\/12\/20\/tcl_createfilehandler-man3-2\/","title":{"rendered":"Tcl_CreateFileHandler (man3)"},"content":{"rendered":"

Tcl_CreateFileHandler<\/h1>\n

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

\n

______________________________________________________________________________<\/p>\n

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

Tcl_CreateFileHandler, Tcl_DeleteFileHandler \u2212 associate procedure callbacks with files or devices (Unix only)<\/p>\n

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

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

Tcl_CreateFileHandler<\/b>(fd, mask, proc, clientData<\/i>)<\/p>\n

Tcl_DeleteFileHandler<\/b>(fd<\/i>)<\/p>\n

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

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

<\/td>\n\n

Unix file descriptor for an open file or device.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

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

<\/td>\n\n

Conditions under which proc<\/i> should be called: OR-ed combination of TCL_READABLE<\/b>, TCL_WRITABLE<\/b>, and TCL_EXCEPTION<\/b>. May be set to 0 to temporarily disable a handler.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

Tcl_FileProc *proc<\/i> (in)<\/p>\n<\/td>\n

<\/td>\n\n

Procedure to invoke whenever the file or device indicated by file<\/i> meets the conditions specified by mask<\/i>.<\/p>\n<\/td>\n<\/tr>\n

<\/td>\n\n

ClientData clientData<\/i> (in)<\/p>\n<\/td>\n

<\/td>\n\n

Arbitrary one-word value to pass to proc<\/i>.<\/p>\n<\/td>\n<\/tr>\n<\/table>\n

______________________________________________________________________________<\/p>\n

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

Tcl_CreateFileHandler<\/b> arranges for proc<\/i> to be invoked in the future whenever I\/O becomes possible on a file or an exceptional condition exists for the file. The file is indicated by fd<\/i>, and the conditions of interest are indicated by mask<\/i>. For example, if mask<\/i> is TCL_READABLE<\/b>, proc<\/i> will be called when the file is readable. The callback to proc<\/i> is made by Tcl_DoOneEvent<\/b>, so Tcl_CreateFileHandler<\/b> is only useful in programs that dispatch events through Tcl_DoOneEvent<\/b> or through Tcl commands such as vwait<\/b>.<\/p>\n

Proc<\/i> should have arguments and result that match the type Tcl_FileProc<\/b>:<\/p>\n

typedef void Tcl_FileProc<\/b>(
ClientData clientData<\/i>,
int mask<\/i>);<\/p>\n

The clientData<\/i> parameter to proc<\/i> is a copy of the clientData<\/i> argument given to Tcl_CreateFileHandler<\/b> when the callback was created. Typically, clientData<\/i> points to a data structure containing application-specific information about the file. Mask<\/i> is an integer mask indicating which of the requested conditions actually exists for the file; it will contain a subset of the bits in the mask<\/i> argument to Tcl_CreateFileHandler<\/b>.<\/p>\n

There may exist only one handler for a given file at a given time. If Tcl_CreateFileHandler<\/b> is called when a handler already exists for fd<\/i>, then the new callback replaces the information that was previously recorded.<\/p>\n

Tcl_DeleteFileHandler<\/b> may be called to delete the file handler for fd<\/i>; if no handler exists for the file given by fd<\/i> then the procedure has no effect.<\/p>\n

The purpose of file handlers is to enable an application to respond to events while waiting for files to become ready for I\/O. For this to work correctly, the application may need to use non-blocking I\/O operations on the files for which handlers are declared. Otherwise the application may block if it reads or writes too much data; while waiting for the I\/O to complete the application will not be able to service other events. Use Tcl_SetChannelOption<\/b> with \u2212blocking<\/b> to set the channel into blocking or nonblocking mode as required.<\/p>\n

Note that these interfaces are only supported by the Unix implementation of the Tcl notifier.<\/p>\n

SEE ALSO <\/a> <\/h2>\n

fileevent(n), Tcl_CreateTimerHandler(3), Tcl_DoWhenIdle(3)<\/p>\n

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

callback, file, handler<\/p>\n

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

Tcl_CreateFileHandler, Tcl_DeleteFileHandler \u2212 associate procedure callbacks with files or devices (Unix only) <\/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":[2538,3007,3505],"class_list":["post-7171","post","type-post","status-publish","format-standard","hentry","category-3-llamadas-de-bibliotecas","tag-2538","tag-man3","tag-tcl_deletefilehandler"],"gutentor_comment":0,"_links":{"self":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/7171","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=7171"}],"version-history":[{"count":0,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/7171\/revisions"}],"wp:attachment":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/media?parent=7171"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/categories?post=7171"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/tags?post=7171"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}