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author | William Joye <wjoye@cfa.harvard.edu> | 2016-12-21 22:46:09 (GMT) |
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committer | William Joye <wjoye@cfa.harvard.edu> | 2016-12-21 22:46:09 (GMT) |
commit | 768f87f613cc9789fcf8073018fa02178c8c91df (patch) | |
tree | ec633f5608ef498bee52a5f42c12c49493ec8bf8 /tcl8.6/doc/Tcl_Main.3 | |
parent | 07e464099b99459d0a37757771791598ef3395d9 (diff) | |
parent | 05fa4c89f20e9769db0e6c0b429cef2590771ace (diff) | |
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Merge commit '05fa4c89f20e9769db0e6c0b429cef2590771ace' as 'tcl8.6'
Diffstat (limited to 'tcl8.6/doc/Tcl_Main.3')
-rw-r--r-- | tcl8.6/doc/Tcl_Main.3 | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/tcl8.6/doc/Tcl_Main.3 b/tcl8.6/doc/Tcl_Main.3 new file mode 100644 index 0000000..3ec33d1 --- /dev/null +++ b/tcl8.6/doc/Tcl_Main.3 @@ -0,0 +1,196 @@ +'\" +'\" Copyright (c) 1994 The Regents of the University of California. +'\" Copyright (c) 1994-1996 Sun Microsystems, Inc. +'\" Copyright (c) 2000 Ajuba Solutions. +'\" +'\" See the file "license.terms" for information on usage and redistribution +'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. +'\" +.TH Tcl_Main 3 8.4 Tcl "Tcl Library Procedures" +.so man.macros +.BS +.SH NAME +Tcl_Main, Tcl_SetStartupScript, Tcl_GetStartupScript, Tcl_SetMainLoop \- main program, startup script, and event loop definition for Tcl-based applications +.SH SYNOPSIS +.nf +\fB#include <tcl.h>\fR +.sp +\fBTcl_Main\fR(\fIargc, argv, appInitProc\fR) +.sp +\fBTcl_SetStartupScript\fR(\fIpath, encoding\fR) +.sp +Tcl_Obj * +\fBTcl_GetStartupScript\fR(\fIencodingPtr\fR) +.sp +\fBTcl_SetMainLoop\fR(\fImainLoopProc\fR) +.SH ARGUMENTS +.AS Tcl_MainLoopProc *mainLoopProc +.AP int argc in +Number of elements in \fIargv\fR. +.AP char *argv[] in +Array of strings containing command-line arguments. On Windows, when +using -DUNICODE, the parameter type changes to wchar_t *. +.AP Tcl_AppInitProc *appInitProc in +Address of an application-specific initialization procedure. +The value for this argument is usually \fBTcl_AppInit\fR. +.AP Tcl_Obj *path in +Name of file to use as startup script, or NULL. +.AP "const char" *encoding in +Encoding of file to use as startup script, or NULL. +.AP "const char" **encodingPtr out +If non-NULL, location to write a copy of the (const char *) +pointing to the encoding name. +.AP Tcl_MainLoopProc *mainLoopProc in +Address of an application-specific event loop procedure. +.BE +.SH DESCRIPTION +.PP +\fBTcl_Main\fR can serve as the main program for Tcl-based shell +applications. A +.QW "shell application" +is a program +like tclsh or wish that supports both interactive interpretation +of Tcl and evaluation of a script contained in a file given as +a command line argument. \fBTcl_Main\fR is offered as a convenience +to developers of shell applications, so they do not have to +reproduce all of the code for proper initialization of the Tcl +library and interactive shell operation. Other styles of embedding +Tcl in an application are not supported by \fBTcl_Main\fR. Those +must be achieved by calling lower level functions in the Tcl library +directly. +.PP +The \fBTcl_Main\fR function has been offered by the Tcl library +since release Tcl 7.4. In older releases of Tcl, the Tcl library +itself defined a function \fBmain\fR, but that lacks flexibility +of embedding style and having a function \fBmain\fR in a library +(particularly a shared library) causes problems on many systems. +Having \fBmain\fR in the Tcl library would also make it hard to use +Tcl in C++ programs, since C++ programs must have special C++ +\fBmain\fR functions. +.PP +Normally each shell application contains a small \fBmain\fR function +that does nothing but invoke \fBTcl_Main\fR. +\fBTcl_Main\fR then does all the work of creating and running a +\fBtclsh\fR-like application. +.PP +\fBTcl_Main\fR is not provided by the public interface of Tcl's +stub library. Programs that call \fBTcl_Main\fR must be linked +against the standard Tcl library. Extensions (stub-enabled or +not) are not intended to call \fBTcl_Main\fR. +.PP +\fBTcl_Main\fR is not thread-safe. It should only be called by +a single master thread of a multi-threaded application. This +restriction is not a problem with normal use described above. +.PP +\fBTcl_Main\fR and therefore all applications based upon it, like +\fBtclsh\fR, use \fBTcl_GetStdChannel\fR to initialize the standard +channels to their default values. See \fBTcl_StandardChannels\fR for +more information. +.PP +\fBTcl_Main\fR supports two modes of operation, depending on +whether the filename and encoding of a startup script has been +established. The routines \fBTcl_SetStartupScript\fR and +\fBTcl_GetStartupScript\fR are the tools for controlling this +configuration of \fBTcl_Main\fR. +.PP +\fBTcl_SetStartupScript\fR registers the value \fIpath\fR +as the name of the file for \fBTcl_Main\fR to evaluate as +its startup script. The value \fIencoding\fR is Tcl's name +for the encoding used to store the text in that file. A +value of \fBNULL\fR for \fIencoding\fR is a signal to use +the system encoding. A value of \fBNULL\fR for \fIpath\fR +erases any existing registration so that \fBTcl_Main\fR +will not evaluate any startup script. +.PP +\fBTcl_GetStartupScript\fR queries the registered file name +and encoding set by the most recent \fBTcl_SetStartupScript\fR +call in the same thread. The stored file name is returned, +and the stored encoding name is written to space pointed to +by \fIencodingPtr\fR, when that is not NULL. +.PP +The file name and encoding values managed by the routines +\fBTcl_SetStartupScript\fR and \fBTcl_GetStartupScript\fR +are stored per-thread. Although the storage and retrieval +functions of these routines work in any thread, only those +calls in the same master thread as \fBTcl_Main\fR can have +any influence on it. +.PP +The caller of \fBTcl_Main\fR may call \fBTcl_SetStartupScript\fR +first to establish its desired startup script. If \fBTcl_Main\fR +finds that no such startup script has been established, it consults +the first few arguments in \fIargv\fR. If they match +?\fB\-encoding \fIname\fR? \fIfileName\fR, +where \fIfileName\fR does not begin with the character \fI\-\fR, +then \fIfileName\fR is taken to be the name of a file containing +a \fIstartup script\fR, and \fIname\fR is taken to be the name +of the encoding of the contents of that file. \fBTcl_Main\fR +then calls \fBTcl_SetStartupScript\fR with these values. +.PP +\fBTcl_Main\fR then defines in its master interpreter +the Tcl variables \fIargc\fR, \fIargv\fR, \fIargv0\fR, and +\fItcl_interactive\fR, as described in the documentation for \fBtclsh\fR. +.PP +When it has finished its own initialization, but before it processes +commands, \fBTcl_Main\fR calls the procedure given by the +\fIappInitProc\fR argument. This procedure provides a +.QW hook +for the application to perform its own initialization of the interpreter +created by \fBTcl_Main\fR, such as defining application-specific +commands. The application initialization routine might also +call \fBTcl_SetStartupScript\fR to (re-)set the file and encoding +to be used as a startup script. The procedure must have an interface +that matches the type \fBTcl_AppInitProc\fR: +.PP +.CS +typedef int \fBTcl_AppInitProc\fR( + Tcl_Interp *\fIinterp\fR); +.CE +.PP +\fIAppInitProc\fR is almost always a pointer to \fBTcl_AppInit\fR; for more +details on this procedure, see the documentation for \fBTcl_AppInit\fR. +.PP +When the \fIappInitProc\fR is finished, \fBTcl_Main\fR calls +\fBTcl_GetStartupScript\fR to determine what startup script has +been requested, if any. If a startup script has been provided, +\fBTcl_Main\fR attempts to evaluate it. Otherwise, interactive +mode begins with examination of the variable \fItcl_rcFileName\fR +in the master interpreter. If that variable exists and holds the +name of a readable file, the contents of that file are evaluated +in the master interpreter. Then interactive operations begin, +with prompts and command evaluation results written to the standard +output channel, and commands read from the standard input channel +and then evaluated. The prompts written to the standard output +channel may be customized by defining the Tcl variables \fItcl_prompt1\fR +and \fItcl_prompt2\fR as described in the documentation for \fBtclsh\fR. +The prompts and command evaluation results are written to the standard +output channel only if the Tcl variable \fItcl_interactive\fR in the +master interpreter holds a non-zero integer value. +.PP +\fBTcl_SetMainLoop\fR allows setting an event loop procedure to be run. +This allows, for example, Tk to be dynamically loaded and set its event +loop. The event loop will run following the startup script. If you +are in interactive mode, setting the main loop procedure will cause the +prompt to become fileevent based and then the loop procedure is called. +When the loop procedure returns in interactive mode, interactive operation +will continue. +The main loop procedure must have an interface that matches the type +\fBTcl_MainLoopProc\fR: +.PP +.CS +typedef void \fBTcl_MainLoopProc\fR(void); +.CE +.PP +\fBTcl_Main\fR does not return. Normally a program based on +\fBTcl_Main\fR will terminate when the \fBexit\fR command is +evaluated. In interactive mode, if an EOF or channel error +is encountered on the standard input channel, then \fBTcl_Main\fR +itself will evaluate the \fBexit\fR command after the main loop +procedure (if any) returns. In non-interactive mode, after +\fBTcl_Main\fR evaluates the startup script, and the main loop +procedure (if any) returns, \fBTcl_Main\fR will also evaluate +the \fBexit\fR command. +.SH "SEE ALSO" +tclsh(1), Tcl_GetStdChannel(3), Tcl_StandardChannels(3), Tcl_AppInit(3), +exit(n), encoding(n) +.SH KEYWORDS +application-specific initialization, command-line arguments, main program |