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diff --git a/doc/load.n b/doc/load.n new file mode 100644 index 0000000..0d5e6e8 --- /dev/null +++ b/doc/load.n @@ -0,0 +1,120 @@ +'\" +'\" Copyright (c) 1995-1996 Sun Microsystems, Inc. +'\" +'\" See the file "license.terms" for information on usage and redistribution +'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. +'\" +'\" SCCS: @(#) load.n 1.9 97/08/22 18:51:18 +'\" +.so man.macros +.TH load n 7.5 Tcl "Tcl Built-In Commands" +.BS +'\" Note: do not modify the .SH NAME line immediately below! +.SH NAME +load \- Load machine code and initialize new commands. +.SH SYNOPSIS +\fBload \fIfileName\fR +.br +\fBload \fIfileName packageName\fR +.br +\fBload \fIfileName packageName interp\fR +.BE + +.SH DESCRIPTION +.PP +This command loads binary code from a file into the +application's address space and calls an initialization procedure +in the package to incorporate it into an interpreter. \fIfileName\fR +is the name of the file containing the code; its exact form varies +from system to system but on most systems it is a shared library, +such as a \fB.so\fR file under Solaris or a DLL under Windows. +\fIpackageName\fR is the name of the package, and is used to +compute the name of an initialization procedure. +\fIinterp\fR is the path name of the interpreter into which to load +the package (see the \fBinterp\fR manual entry for details); +if \fIinterp\fR is omitted, it defaults to the +interpreter in which the \fBload\fR command was invoked. +.PP +Once the file has been loaded into the application's address space, +one of two initialization procedures will be invoked in the new code. +Typically the initialization procedure will add new commands to a +Tcl interpreter. +The name of the initialization 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_Init\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_Init\fR. +.PP +If the target interpreter is a safe interpreter, then the name +of the initialization procedure will be \fIpkg\fB_SafeInit\fR +instead of \fIpkg\fB_Init\fR. +The \fIpkg\fB_SafeInit\fR function should be written carefully, so that it +initializes the safe interpreter only with partial functionality provided +by the package that is safe for use by untrusted code. For more information +on Safe\-Tcl, see the \fBsafe\fR manual entry. +.PP +The initialization procedure must match the following prototype: +.CS +typedef int Tcl_PackageInitProc(Tcl_Interp *\fIinterp\fR); +.CE +The \fIinterp\fR argument identifies the interpreter in which the +package is to be loaded. The initialization 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 \fIinterp->result\fR +to point to an error message. The result of the \fBload\fR command +will be the result returned by the initialization procedure. +.PP +The actual loading of a file will only be done once for each \fIfileName\fR +in an application. If a given \fIfileName\fR is loaded into multiple +interpreters, then the first \fBload\fR will load the code and +call the initialization procedure; subsequent \fBload\fRs will +call the initialization procedure without loading the code again. +It is not possible to unload or reload a package. +.PP +The \fBload\fR command also supports packages that are statically +linked with the application, if those packages have been registered +by calling the \fBTcl_StaticPackage\fR procedure. +If \fIfileName\fR is an empty string, then \fIpackageName\fR 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 +.VS +alphabetic and underline characters as the module name. +.VE +For example, the command \fBload libxyz4.2.so\fR uses the module +name \fBxyz\fR and the command \fBload bin/last.so {}\fR uses the +module name \fBlast\fR. +.VS "" br +.PP +If \fIfileName\fR is an empty string, then \fIpackageName\fR must +be specified. +The \fBload\fR command first searches for a statically loaded package +(one that has been registered by calling the \fBTcl_StaticPackage\fR +procedure) by that name; if one is found, it is used. +Otherwise, the \fBload\fR command searches for a dynamically loaded +package by that name, and uses it if it is found. If several +different files have been \fBload\fRed with different versions of +the package, Tcl picks the file that was loaded first. +.VE + +.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). + +.SH "SEE ALSO" +\fBinfo sharedlibextension\fR, Tcl_StaticPackage, safe(n) + +.SH KEYWORDS +binary code, loading, safe interpreter, shared library |