Tcl SCCS: @(#) README 1.38 96/10/07 11:33:23 1. Introduction --------------- This directory and its descendants contain the sources and documentation for Tcl, an embeddable scripting language. The information here corresponds to release 7.6. This is a relatively minor release with bug fixes and a few new features, mostly to improve portability. Tcl 7.6 should be backwards compatible with Tcl 7.5 scripts, but there are two incompatible changes, one in the C APIs for custom channel drivers and the other affecting start-up file names under Windows. See below for more details. 2. Documentation ---------------- The best way to get started with Tcl is to read one of the introductory books on Tcl: Tcl and the Tk Toolkit, by John Ousterhout, Addison-Wesley, 1994, ISBN 0-201-63337-X Practical Programming in Tcl and Tk, by Brent Welch, Prentice-Hall, 1995, ISBN 0-13-182007-9 Exploring Expect, by Don Libes, O'Reilly and Associates, 1995, ISBN 1-56592-090-2 The "doc" subdirectory in this release contains a complete set of reference manual entries for Tcl. Files with extension ".1" are for programs (for example, tclsh.1); files with extension ".3" are for C library procedures; and files with extension ".n" describe Tcl commands. The file "doc/Tcl.n" gives a quick summary of the Tcl language syntax. To print any of the man pages, cd to the "doc" directory and invoke your favorite variant of troff using the normal -man macros, for example ditroff -man Tcl.n to print Tcl.n. If Tcl has been installed correctly and your "man" program supports it, you should be able to access the Tcl manual entries using the normal "man" mechanisms, such as man Tcl There is also an official home for Tcl and Tk on the Web: http://www.sunlabs.com/research/tcl These Web pages include release updates, reports on bug fixes and porting issues, HTML versions of the manual pages, and pointers to many other Tcl/Tk Web pages at other sites. Check them out! 3. Compiling and installing Tcl ------------------------------- This release contains everything you should need to compile and run Tcl under UNIX, Macintoshes, and PCs (either Windows NT, Windows 95, or Win 3.1 with Win32s). Before trying to compile Tcl you should do the following things: (a) Check for a binary release. Pre-compiled binary releases are available now for PCs, Macintoshes, and several flavors of UNIX. Binary releases are much easier to install than source releases. To find out whether a binary release is available for your platform, check the home page for the Sun Tcl/Tk project (http://www.sunlabs.com/research/tcl) and also check in the FTP directory from which you retrieved the base distribution. Some of the binary releases are available freely, while others are for sale. (b) Make sure you have the most recent patch release. Look in the FTP directory from which you retrieved this distribution to see if it has been updated with patches. Patch releases fix bugs without changing any features, so you should normally use the latest patch release for the version of Tcl that you want. Patch releases are available in two forms. A file like tcl7.6p1.tar.Z is a complete release for patch level 1 of Tcl version 7.6. If there is a file with a higher patch level than this release, just fetch the file with the highest patch level and use it. Patches are also available in the form of patch files that just contain the changes from one patch level to another. These files will have names like tcl7.6p1.patch, tcl7.6p2.patch, etc. They may also have .gz or .Z extensions to indicate compression. To use one of these files, you apply it to an existing release with the "patch" program. Patches must be applied in order: tcl7.6p1.patch must be applied to an unpatched Tcl 7.6 release to produce a Tcl 7.6p1 release; tcl7.6p2.patch can then be applied to Tcl7.6p1 to produce Tcl 7.6p2, and so on. To apply an uncompressed patch file such as tcl7.6p1.patch, invoke a shell command like the following from the directory containing this file: patch -p < tcl7.6p1.patch If the patch file has a .gz extension, invoke a command like the following: gunzip -c tcl7.6p1.patch.gz | patch -p If the patch file has a .Z extension, it was compressed with compress. To apply it, invoke a command like the following: zcat tcl7.6p1.patch.Z | patch -p If you're applying a patch to a release that has already been compiled, then before applying the patch you should cd to the "unix" subdirectory and type "make distclean" to restore the directory to a pristine state. Once you've done this, change to the "unix" subdirectory if you're compiling under UNIX, "win" if you're compiling under Windows, or "mac" if you're compiling on a Macintosh. Then follow the instructions in the README file in that directory for compiling Tcl, installing it, and running the test suite. 4. Summary of changes in Tcl 7.6 -------------------------------- Here are the most significant changes in Tcl 7.6. In addition to these changes, there are numerous small bug fixes. See the file "changes" for a complete list of all changes. 1. New file manipulation commands. There are new options to the "file" command for copying files ("file copy"), deleting files and directories ("file delete"), creating directories ("file mkdir"), and renaming files ("file rename"). 2. The implementation of "exec" has been improved greatly for Windows 95 and Windows NT. 3. The package loader has been modified to look for packages not only in the auto_path directories but also in their immediate descendants. This makes it much easier to install and uninstall packages. There is now a new variable, tcl_pkgPath, which contains directories in which packages are normally installed, and these directories are automatically included in auto_path. 4. There is a new memory allocator for the Macintosh version, which should be more efficient than the old one. Tcl 7.6 contains two incompatible changes: 1. The C interfaces to channel drivers have been revised to eliminate the use of Tcl_File handles in the interfaces. Instead, there are new interface procedures channelReadyProc, watchChannelProc, and getFileProc. This change does not affect Tcl scripts; it will only affect you if you have written a custom channel driver. 2. Under Windows, tclsh now looks for the start-up file "tclshrc.tcl" instead of "tclsh.rc". This is more consistent with wish and uses the right extension. 5. Tcl newsgroup ----------------- There is a network news group "comp.lang.tcl" intended for the exchange of information about Tcl, Tk, and related applications. Feel free to use the newsgroup both for general information questions and for bug reports. We read the newsgroup and will attempt to fix bugs and problems reported to it. When using comp.lang.tcl, please be sure that your e-mail return address is correctly set in your postings. This allows people to respond directly to you, rather than the entire newsgroup, for answers that are not of general interest. A bad e-mail return address may prevent you from getting answers to your questions. You may have to reconfigure your news reading software to ensure that it is supplying valid e-mail addresses. 6. Tcl contributed archive -------------------------- Many people have created exciting packages and applications based on Tcl and/or Tk and made them freely available to the Tcl community. An archive of these contributions is kept on the machine ftp.neosoft.com. You can access the archive using anonymous FTP; the Tcl contributed archive is in the directory "/pub/tcl". The archive also contains several FAQ ("frequently asked questions") documents that provide solutions to problems that are commonly encountered by TCL newcomers. 7. Support and bug fixes ------------------------ We're very interested in receiving bug reports and suggestions for improvements. We prefer that you send this information to the comp.lang.tcl newsgroup rather than to any of us at Sun. We'll see anything on comp.lang.tcl, and in addition someone else who reads comp.lang.tcl may be able to offer a solution. The normal turn-around time for bugs is 3-6 weeks. Enhancements may take longer and may not happen at all unless there is widespread support for them (we're trying to slow the rate at which Tcl turns into a kitchen sink). It's very difficult to make incompatible changes to Tcl at this point, due to the size of the installed base. When reporting bugs, please provide a short tclsh script that we can use to reproduce the bug. Make sure that the script runs with a bare-bones tclsh and doesn't depend on any extensions or other programs, particularly those that exist only at your site. Also, please include three additional pieces of information with the script: (a) how do we use the script to make the problem happen (e.g. what things do we click on, in what order)? (b) what happens when you do these things (presumably this is undesirable)? (c) what did you expect to happen instead? The Tcl community is too large for us to provide much individual support for users. If you need help we suggest that you post questions to comp.lang.tcl. We read the newsgroup and will attempt to answer esoteric questions for which no-one else is likely to know the answer. In addition, Tcl support and training are available commercially from NeoSoft (info@neosoft.com), Computerized Processes Unlimited (gwl@cpu.com), and Data Kinetics (education@dkl.com). 8. Tcl version numbers ---------------------- Each Tcl release is identified by two numbers separated by a dot, e.g. 6.7 or 7.0. If a new release contains changes that are likely to break existing C code or Tcl scripts then the major release number increments and the minor number resets to zero: 6.0, 7.0, etc. If a new release contains only bug fixes and compatible changes, then the minor number increments without changing the major number, e.g. 7.1, 7.2, etc. If you have C code or Tcl scripts that work with release X.Y, then they should also work with any release X.Z as long as Z > Y. Alpha and beta releases have an additional suffix of the form a2 or b1. For example, Tcl 7.0b1 is the first beta release of Tcl version 7.0, Tcl 7.0b2 is the second beta release, and so on. A beta release is an initial version of a new release, used to fix bugs and bad features before declaring the release stable. An alpha release is like a beta release, except it's likely to need even more work before it's "ready for prime time". New releases are normally preceded by one or more alpha and beta releases. We hope that lots of people will try out the alpha and beta releases and report problems. We'll make new alpha/beta releases to fix the problems, until eventually there is a beta release that appears to be stable. Once this occurs we'll make the final release. We can't promise to maintain compatibility among alpha and beta releases. For example, release 7.1b2 may not be backward compatible with 7.1b1, even though the final 7.1 release will be backward compatible with 7.0. This allows us to change new features as we find problems during beta testing. We'll try to minimize incompatibilities between beta releases, but if a major problem turns up then we'll fix it even if it introduces an incompatibility. Once the official release is made then there won't be any more incompatibilities until the next release with a new major version number. Patch releases have a suffix such as p1 or p2. These releases contain bug fixes only. A patch release (e.g Tcl 7.6p2) should be completely compatible with the base release from which it is derived (e.g. Tcl 7.6), and you should normally use the highest available patch release.