106 lines
4.4 KiB
Plaintext
106 lines
4.4 KiB
Plaintext
'\"
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'\" Copyright (c) 1995-1996 Sun Microsystems, Inc.
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'\"
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'\" See the file "license.terms" for information on usage and redistribution
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'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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'\"
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'\" SCCS: @(#) load.n 1.5 96/03/25 20:19:39
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'\"
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.so man.macros
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.TH load n 7.5 Tcl "Tcl Built-In Commands"
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.BS
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'\" Note: do not modify the .SH NAME line immediately below!
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.SH NAME
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load \- Load machine code and initialize new commands.
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.SH SYNOPSIS
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\fBload \fIfileName\fR
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.br
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\fBload \fIfileName packageName\fR
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.br
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\fBload \fIfileName packageName interp\fR
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.BE
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.SH DESCRIPTION
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.PP
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This command loads binary code from a file into the
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application's address space and calls an initialization procedure
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in the package to incorporate it into an interpreter. \fIfileName\fR
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is the name of the file containing the code; its exact form varies
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from system to system but on most systems it is a shared library,
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such as a \fB.so\fR file under Solaris or a DLL under Windows.
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\fIpackageName\fR is the name of the package, and is used to
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compute the name of an initialization procedure.
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\fIinterp\fR is the path name of the interpreter into which to load
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the package (see the \fBinterp\fR manual entry for details);
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if \fIinterp\fR is omitted, it defaults to the
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interpreter in which the \fBload\fR command was invoked.
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.PP
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Once the file has been loaded into the application's address space,
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one of two initialization procedures will be invoked in the new code.
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Typically the initialization procedure will add new commands to a
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Tcl interpreter.
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The name of the initialization procedure is determined by
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\fIpackageName\fR and whether or not the target interpreter
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is a safe one. For normal interpreters the name of the initialization
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procedure will have the form \fIpkg\fB_Init\fR, where \fIpkg\fR
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is the same as \fIpackageName\fR except that the first letter is
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converted to upper case and all other letters
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are converted to lower case. For example, if \fIpackageName\fR is
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\fBfoo\fR or \fBFOo\fR, the initialization procedure's name will
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be \fBFoo_Init\fR.
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.PP
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If the target interpreter is a safe interpreter, then the name
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of the initialization procedure will be \fIpkg\fB_SafeInit\fR
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instead of \fIpkg\fB_Init\fR.
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.PP
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The initialization procedure must match the following prototype:
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.CS
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typedef int Tcl_PackageInitProc(Tcl_Interp *\fIinterp\fR);
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.CE
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The \fIinterp\fR argument identifies the interpreter in which the
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package is to be loaded. The initialization procedure must return
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\fBTCL_OK\fR or \fBTCL_ERROR\fR to indicate whether or not it completed
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successfully; in the event of an error it should set \fIinterp->result\fR
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to point to an error message. The result of the \fBload\fR command
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will be the result returned by the initialization procedure.
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.PP
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The actual loading of a file will only be done once for each \fIfileName\fR
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in an application. If a given \fIfileName\fR is loaded into multiple
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interpreters, then the first \fBload\fR will load the code and
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call the initialization procedure; subsequent \fBload\fRs will
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call the initialization procedure without loading the code again.
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It is not possible to unload or reload a package.
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.PP
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The \fBload\fR command also supports packages that are statically
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linked with the application, if those packages have been registered
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by calling the \fBTcl_StaticPackage\fR procedure.
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If \fIfileName\fR is an empty string, then \fIpackageName\fR must
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be specified and it must give the name of a statically loaded
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package.
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The appropriate initialization procedure for that package will then
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be invoked to incorporate the package into the target interpreter.
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.PP
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If \fIpackageName\fR is omitted or specified as an empty string,
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Tcl tries to guess the name of the package.
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This may be done differently on different platforms.
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The default guess, which is used on most UNIX platforms, is to
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take the last element of \fIfileName\fR, strip off the first
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three characters if they are \fBlib\fR, and use any following
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alphabetic characters as the module name.
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For example, the command \fBload libxyz4.2.so\fR uses the module
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name \fBxyz\fR and the command \fBload bin/last.so {}\fR uses the
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module name \fBlast\fR.
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.SH BUGS
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.PP
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If the same file is \fBload\fRed by different \fIfileName\fRs, it will
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be loaded into the process's address space multiple times. The
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behavior of this varies from system to system (some systems may
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detect the redundant loads, others may not).
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.SH "SEE ALSO"
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\fBinfo sharedlibextension\fR, Tcl_StaticPackage
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.SH KEYWORDS
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binary code, loading, shared library
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