'\"
'\" Copyright (c) 2009-2010 Kevin B. Kenny
'\" Copyright (c) 2010 Donal K. Fellows
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\"
.TH Load 3tcl 8.6 Tcl "Tcl Library Procedures"
.\" The -*- nroff -*- definitions below are for supplemental macros used
.\" in Tcl/Tk manual entries.
.\"
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.\"	Start paragraph describing an argument to a library procedure.
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.\"	or "in/out" to describe whether procedure reads or modifies arg,
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.\" .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
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.\"
.\" .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
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.\" .UL arg1 arg2
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.\"	(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
..
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.\"	# ^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
..
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.de VE
.ie n 'mc
.el \{\
.ev 2
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.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
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.de ^B
.ev 2
'ti 0
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.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
.\}
..
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.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
..
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.de CS
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.nf
.ta .25i .5i .75i 1i
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.de CE
.fi
.RE
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.de UL
\\$1\l'|0\(ul'\\$2
..
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.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 ""
..
.BS
.SH NAME
Tcl_LoadFile, Tcl_FindSymbol \- platform-independent dynamic library loading
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR
.sp
int
\fBTcl_LoadFile\fR(\fIinterp, pathPtr, symbols, flags, procPtrs, loadHandlePtr\fR)
.sp
void *
\fBTcl_FindSymbol\fR(\fIinterp, loadHandle, symbol\fR)
.SH ARGUMENTS
.AS Tcl_LoadHandle loadHandle in
.AP Tcl_Interp *interp in
Interpreter to use for reporting error messages.
.AP Tcl_Obj *pathPtr in
The name of the file to load. If it is a single name, the library search path
of the current environment will be used to resolve it.
.AP "const char *const" symbols[] in
Array of names of symbols to be resolved during the load of the library, or
NULL if no symbols are to be resolved. If an array is given, the last entry in
the array must be NULL.
.AP int flags in
The value should normally be 0, but \fITCL_LOAD_GLOBAL\fR or \fITCL_LOAD_LAZY\fR
or a combination of those two is allowed as well.
.AP void *procPtrs out
Points to an array that will hold the addresses of the functions described in
the \fIsymbols\fR argument. Should be NULL if no symbols are to be resolved.
.AP Tcl_LoadHandle *loadHandlePtr out
Points to a variable that will hold the handle to the abstract token
describing the library that has been loaded.
.AP Tcl_LoadHandle loadHandle in
Abstract token describing the library to look up a symbol in.
.AP "const char" *symbol in
The name of the symbol to look up.
.BE
.SH DESCRIPTION
.PP
\fBTcl_LoadFile\fR loads a file from the filesystem (including potentially any
virtual filesystem that has been installed) and provides a handle to it that
may be used in further operations. The \fIsymbols\fR array, if non-NULL,
supplies a set of names of symbols (typically functions) that must be resolved
from the library and which will be stored in the array indicated by
\fIprocPtrs\fR. If any of the symbols is not resolved, the loading of the file
will fail with an error message left in the interpreter (if that is non-NULL).
The result of \fBTcl_LoadFile\fR is a standard Tcl error code. The library may
be unloaded with \fBTcl_FSUnloadFile\fR.
.PP
\fBTcl_FindSymbol\fR locates a symbol in a loaded library and returns it. If
the symbol cannot be found, it returns NULL and sets an error message in the
given \fIinterp\fR (if that is non-NULL). Note that it is unsafe to use this
operation on a handle that has been passed to \fBTcl_FSUnloadFile\fR.
.SH "REFERENCE COUNT MANAGEMENT"
.PP
The reference count of the \fIpathPtr\fR argument to \fBTcl_LoadFile\fR may be
incremented. As such, it should not be given a zero reference count value.
.SH "SEE ALSO"
Tcl_FSLoadFile(3tcl), Tcl_FSUnloadFile(3tcl), load(3tcl), unload(3tcl)
.SH KEYWORDS
binary code, loading, shared library
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