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author | Shashank | 2017-05-29 12:40:26 +0530 |
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committer | Shashank | 2017-05-29 12:40:26 +0530 |
commit | 0345245e860375a32c9a437c4a9d9cae807134e9 (patch) | |
tree | ad51ecbfa7bcd3cc5f09834f1bb8c08feaa526a4 /usr/man/mann/unload.n | |
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diff --git a/usr/man/mann/unload.n b/usr/man/mann/unload.n new file mode 100755 index 000000000..4b81e8531 --- /dev/null +++ b/usr/man/mann/unload.n @@ -0,0 +1,428 @@ +'\" +'\" Copyright (c) 2003 George Petasis <petasis@iit.demokritos.gr>. +'\" +'\" See the file "license.terms" for information on usage and redistribution +'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. +'\" +.\" The -*- nroff -*- definitions below are for supplemental macros used +.\" in Tcl/Tk manual entries. +.\" +.\" .AP type name in/out ?indent? +.\" Start paragraph describing an argument to a library procedure. +.\" type is type of argument (int, etc.), in/out is either "in", "out", +.\" or "in/out" to describe whether procedure reads or modifies arg, +.\" and indent is equivalent to second arg of .IP (shouldn't ever be +.\" needed; use .AS below instead) +.\" +.\" .AS ?type? ?name? +.\" Give maximum sizes of arguments for setting tab stops. Type and +.\" name are examples of largest possible arguments that will be passed +.\" to .AP later. If args are omitted, default tab stops are used. +.\" +.\" .BS +.\" Start box enclosure. From here until next .BE, everything will be +.\" enclosed in one large box. +.\" +.\" .BE +.\" End of box enclosure. +.\" +.\" .CS +.\" Begin code excerpt. +.\" +.\" .CE +.\" End code excerpt. +.\" +.\" .VS ?version? ?br? +.\" Begin vertical sidebar, for use in marking newly-changed parts +.\" of man pages. The first argument is ignored and used for recording +.\" the version when the .VS was added, so that the sidebars can be +.\" found and removed when they reach a certain age. If another argument +.\" is present, then a line break is forced before starting the sidebar. +.\" +.\" .VE +.\" End of vertical sidebar. +.\" +.\" .DS +.\" Begin an indented unfilled display. +.\" +.\" .DE +.\" End of indented unfilled display. +.\" +.\" .SO ?manpage? +.\" Start of list of standard options for a Tk widget. The manpage +.\" argument defines where to look up the standard options; if +.\" omitted, defaults to "options". The options follow on successive +.\" lines, in three columns separated by tabs. +.\" +.\" .SE +.\" End of list of standard options for a Tk widget. +.\" +.\" .OP cmdName dbName dbClass +.\" Start of description of a specific option. cmdName gives the +.\" option's name as specified in the class command, dbName gives +.\" the option's name in the option database, and dbClass gives +.\" the option's class in the option database. +.\" +.\" .UL arg1 arg2 +.\" Print arg1 underlined, then print arg2 normally. +.\" +.\" .QW arg1 ?arg2? +.\" Print arg1 in quotes, then arg2 normally (for trailing punctuation). +.\" +.\" .PQ arg1 ?arg2? +.\" Print an open parenthesis, arg1 in quotes, then arg2 normally +.\" (for trailing punctuation) and then a closing parenthesis. +.\" +.\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. +.if t .wh -1.3i ^B +.nr ^l \n(.l +.ad b +.\" # Start an argument description +.de AP +.ie !"\\$4"" .TP \\$4 +.el \{\ +. ie !"\\$2"" .TP \\n()Cu +. el .TP 15 +.\} +.ta \\n()Au \\n()Bu +.ie !"\\$3"" \{\ +\&\\$1 \\fI\\$2\\fP (\\$3) +.\".b +.\} +.el \{\ +.br +.ie !"\\$2"" \{\ +\&\\$1 \\fI\\$2\\fP +.\} +.el \{\ +\&\\fI\\$1\\fP +.\} +.\} +.. +.\" # define tabbing values for .AP +.de AS +.nr )A 10n +.if !"\\$1"" .nr )A \\w'\\$1'u+3n +.nr )B \\n()Au+15n +.\" +.if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n +.nr )C \\n()Bu+\\w'(in/out)'u+2n +.. +.AS Tcl_Interp Tcl_CreateInterp in/out +.\" # BS - start boxed text +.\" # ^y = starting y location +.\" # ^b = 1 +.de BS +.br +.mk ^y +.nr ^b 1u +.if n .nf +.if n .ti 0 +.if n \l'\\n(.lu\(ul' +.if n .fi +.. +.\" # BE - end boxed text (draw box now) +.de BE +.nf +.ti 0 +.mk ^t +.ie n \l'\\n(^lu\(ul' +.el \{\ +.\" Draw four-sided box normally, but don't draw top of +.\" box if the box started on an earlier page. +.ie !\\n(^b-1 \{\ +\h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' +.\} +.el \}\ +\h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' +.\} +.\} +.fi +.br +.nr ^b 0 +.. +.\" # VS - start vertical sidebar +.\" # ^Y = starting y location +.\" # ^v = 1 (for troff; for nroff this doesn't matter) +.de VS +.if !"\\$2"" .br +.mk ^Y +.ie n 'mc \s12\(br\s0 +.el .nr ^v 1u +.. +.\" # VE - end of vertical sidebar +.de VE +.ie n 'mc +.el \{\ +.ev 2 +.nf +.ti 0 +.mk ^t +\h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' +.sp -1 +.fi +.ev +.\} +.nr ^v 0 +.. +.\" # Special macro to handle page bottom: finish off current +.\" # box/sidebar if in box/sidebar mode, then invoked standard +.\" # page bottom macro. +.de ^B +.ev 2 +'ti 0 +'nf +.mk ^t +.if \\n(^b \{\ +.\" Draw three-sided box if this is the box's first page, +.\" draw two sides but no top otherwise. +.ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c +.el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c +.\} +.if \\n(^v \{\ +.nr ^x \\n(^tu+1v-\\n(^Yu +\kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c +.\} +.bp +'fi +.ev +.if \\n(^b \{\ +.mk ^y +.nr ^b 2 +.\} +.if \\n(^v \{\ +.mk ^Y +.\} +.. +.\" # DS - begin display +.de DS +.RS +.nf +.sp +.. +.\" # DE - end display +.de DE +.fi +.RE +.sp +.. +.\" # SO - start of list of standard options +.de SO +'ie '\\$1'' .ds So \\fBoptions\\fR +'el .ds So \\fB\\$1\\fR +.SH "STANDARD OPTIONS" +.LP +.nf +.ta 5.5c 11c +.ft B +.. +.\" # SE - end of list of standard options +.de SE +.fi +.ft R +.LP +See the \\*(So manual entry for details on the standard options. +.. +.\" # OP - start of full description for a single option +.de OP +.LP +.nf +.ta 4c +Command-Line Name: \\fB\\$1\\fR +Database Name: \\fB\\$2\\fR +Database Class: \\fB\\$3\\fR +.fi +.IP +.. +.\" # CS - begin code excerpt +.de CS +.RS +.nf +.ta .25i .5i .75i 1i +.. +.\" # CE - end code excerpt +.de CE +.fi +.RE +.. +.\" # UL - underline word +.de UL +\\$1\l'|0\(ul'\\$2 +.. +.\" # QW - apply quotation marks to word +.de QW +.ie '\\*(lq'"' ``\\$1''\\$2 +.\"" fix emacs highlighting +.el \\*(lq\\$1\\*(rq\\$2 +.. +.\" # PQ - apply parens and quotation marks to word +.de PQ +.ie '\\*(lq'"' (``\\$1''\\$2)\\$3 +.\"" fix emacs highlighting +.el (\\*(lq\\$1\\*(rq\\$2)\\$3 +.. +.\" # QR - quoted range +.de QR +.ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3 +.\"" fix emacs highlighting +.el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3 +.. +.\" # MT - "empty" string +.de MT +.QW "" +.. +.TH unload n 8.5 Tcl "Tcl Built-In Commands" +.BS +'\" Note: do not modify the .SH NAME line immediately below! +.SH NAME +unload \- Unload machine code +.SH SYNOPSIS +\fBunload \fR?\fIswitches\fR? \fIfileName\fR +.br +\fBunload \fR?\fIswitches\fR? \fIfileName packageName\fR +.br +\fBunload \fR?\fIswitches\fR? \fIfileName packageName interp\fR +.BE +.SH DESCRIPTION +.PP +This command tries to unload shared libraries previously loaded +with \fBload\fR from the application's address space. \fIfileName\fR +is the name of the file containing the library file to be unload; it +must be the same as the filename provided to \fBload\fR for +loading the library. +The \fIpackageName\fR argument is the name of the package (as +determined by or passed to \fBload\fR), and is used to +compute the name of the unload procedure; if not supplied, it is +computed from \fIfileName\fR in the same manner as \fBload\fR. +The \fIinterp\fR argument is the path name of the interpreter from +which to unload the package (see the \fBinterp\fR manual entry for +details); if \fIinterp\fR is omitted, it defaults to the +interpreter in which the \fBunload\fR command was invoked. +.PP +If the initial arguments to \fBunload\fR start with \fB\-\fR then +they are treated as switches. The following switches are +currently supported: +.TP +\fB\-nocomplain\fR +. +Suppresses all error messages. If this switch is given, \fBunload\fR will +never report an error. +.TP +\fB\-keeplibrary\fR +. +This switch will prevent \fBunload\fR from issuing the operating system call +that will unload the library from the process. +.TP +\fB\-\|\-\fR +. +Marks the end of switches. The argument following this one will +be treated as a \fIfileName\fR even if it starts with a \fB\-\fR. +.SS "UNLOAD OPERATION" +.PP +When a file containing a shared library is loaded through the +\fBload\fR command, Tcl associates two reference counts to the library +file. The first counter shows how many times the library has been +loaded into normal (trusted) interpreters while the second describes how many +times the library has been loaded into safe interpreters. As a file containing +a shared library can be loaded only once by Tcl (with the first \fBload\fR +call on the file), these counters track how many interpreters use the library. +Each subsequent call to \fBload\fR after the first simply increments the +proper reference count. +.PP +\fBunload\fR works in the opposite direction. As a first step, \fBunload\fR +will check whether the library is unloadable: an unloadable library exports +a special unload procedure. The name of the unload procedure is determined by +\fIpackageName\fR and whether or not the target interpreter +is a safe one. For normal interpreters the name of the initialization +procedure will have the form \fIpkg\fB_Unload\fR, where \fIpkg\fR +is the same as \fIpackageName\fR except that the first letter is +converted to upper case and all other letters +are converted to lower case. For example, if \fIpackageName\fR is +\fBfoo\fR or \fBFOo\fR, the initialization procedure's name will +be \fBFoo_Unload\fR. +If the target interpreter is a safe interpreter, then the name +of the initialization procedure will be \fIpkg\fB_SafeUnload\fR +instead of \fIpkg\fB_Unload\fR. +.PP +If \fBunload\fR determines that a library is not unloadable (or unload +functionality has been disabled during compilation), an error will be returned. +If the library is unloadable, then \fBunload\fR will call the unload +procedure. If the unload procedure returns \fBTCL_OK\fR, \fBunload\fR will proceed +and decrease the proper reference count (depending on the target interpreter +type). When both reference counts have reached 0, the library will be +detached from the process. +.SS "UNLOAD HOOK PROTOTYPE" +.PP +The unload procedure must match the following prototype: +.CS +typedef int Tcl_PackageUnloadProc(Tcl_Interp *\fIinterp\fR, int \fIflags\fR); +.CE +.PP +The \fIinterp\fR argument identifies the interpreter from which the +library is to be unloaded. The unload procedure must return +\fBTCL_OK\fR or \fBTCL_ERROR\fR to indicate whether or not it completed +successfully; in the event of an error it should set the interpreter's result +to point to an error message. In this case, the result of the +\fBunload\fR command will be the result returned by the unload procedure. +.PP +The \fIflags\fR argument can be either \fBTCL_UNLOAD_DETACH_FROM_INTERPRETER\fR +or \fBTCL_UNLOAD_DETACH_FROM_PROCESS\fR. In case the library will remain +attached to the process after the unload procedure returns (i.e. because +the library is used by other interpreters), +\fBTCL_UNLOAD_DETACH_FROM_INTERPRETER\fR will be defined. However, if the +library is used only by the target interpreter and the library will be +detached from the application as soon as the unload procedure returns, +the \fIflags\fR argument will be set to \fBTCL_UNLOAD_DETACH_FROM_PROCESS\fR. +.SS NOTES +.PP +The \fBunload\fR command cannot unload libraries that are statically +linked with the application. +If \fIfileName\fR is an empty string, then the \fIpackageName\fR argument must +be specified. +.PP +If \fIpackageName\fR is omitted or specified as an empty string, +Tcl tries to guess the name of the package. +This may be done differently on different platforms. +The default guess, which is used on most UNIX platforms, is to +take the last element of \fIfileName\fR, strip off the first +three characters if they are \fBlib\fR, and use any following +alphabetic and underline characters as the module name. +For example, the command \fBunload libxyz4.2.so\fR uses the module +name \fBxyz\fR and the command \fBunload bin/last.so {}\fR uses the +module name \fBlast\fR. +.SH "PORTABILITY ISSUES" +.TP +\fBUnix\fR\0\0\0\0\0 +. +Not all unix operating systems support library unloading. Under such +an operating system \fBunload\fR returns an error (unless \fB\-nocomplain\fR +has been specified). +.SH BUGS +.PP +If the same file is \fBload\fRed by different \fIfileName\fRs, it will +be loaded into the process's address space multiple times. The +behavior of this varies from system to system (some systems may +detect the redundant loads, others may not). In case a library has been +silently detached by the operating system (and as a result Tcl thinks the +library is still loaded), it may be dangerous to use +\fBunload\fR on such a library (as the library will be completely detached +from the application while some interpreters will continue to use it). +.SH EXAMPLE +If an unloadable module in the file \fBfoobar.dll\fR had been loaded +using the \fBload\fR command like this (on Windows): +.CS +load c:/some/dir/foobar.dll +.CE +then it would be unloaded like this: +.CS +\fBunload\fR c:/some/dir/foobar.dll +.CE +.PP +This allows a C code module to be installed temporarily into a +long-running Tcl program and then removed again (either because it is +no longer needed or because it is being updated with a new version) +without having to shut down the overall Tcl process. +.SH "SEE ALSO" +info sharedlibextension, load(n), safe(n) +.SH KEYWORDS +binary code, unloading, safe interpreter, shared library |