用TCL编写 的小程序

A sample dynamically loadable extension for Tcl 7.5 by Scott Stanton w/ help from Ray Johnson scott.stanton@eng.sun.com ray.johnson@eng.sun.com SCCS: @(#) README 1.6 96/04/26 11:36:47 1. Introduction --------------- Version 7.5 of Tcl now has the ability to dynamically load binary Tcl extensions at run time. See the load command for details on how to do this from Tcl. This distribution provides a very simple example on how to build a binary Tcl extension on the various major platforms. This directory contains a sample dynamically loadable extension for Tcl 7.5. This extension demonstrates the techniques needed to add a new command to Tcl in a cross platform manner. You should be able to use this example as a template for building your own extensions. 2. Compiling the example ------------------------ For Unix systems: (a) Make sure that the Tcl 7.5 release is present in the directory ../tcl7.5. This example will only work with Tcl 7.5. Also, be sure that you have configured Tcl before you configure the example. You can obtain the Tcl 7.5 release by anonymous ftp from ftp.sunlabs.com:/pub/tcl. (b) Type "./configure". This runs a configuration script created by GNU autoconf, which configures Tcl for your system and creates a Makefile. The configure script allows you to customize the Tcl configuration for your site; for details on how you can do this, type "./configure -help" or refer to the autoconf documentation (not included here). Note: the example will use the same C compiler (e.g. gcc) as Tcl, as well as several other of Tcl's configuration options. You should not usually modify CC in the Makefile generated here (if do you, be sure to check all of the definitions related to dynamic loading to make sure that they are still correct). The example "configure" supports the following special switches in addition to the standard ones: --with-tcl=DIR Specifies the directory containing the Tcl binaries and Tcl's platform-dependent configuration information. By default the Tcl directory is assumed to be in the location given by (a) above. (c) Type "make". This will create a shared library called "example.so" and a package index file called "pkgIndex.tcl". (d) Type "make test" to test the example. This will attempt to load the example package from the current directory. If it succeeds, you will see the message "Test passed.", otherwise you will see an error. For Microsoft Windows systems: (a) Make sure that you have installed the Tcl 7.5 binary release. Because most "make" programs don't support long file names, you should install Tcl into a directory that does not contain spaces in the name. This is primarily an issue under Windows 95, since the default location is under the "Program Files" directory. (b) If you are using the Borland compilers: 1. Copy the file "makefile.bc" to the file "makefile". 2. Edit "makefile" and change the BORLAND and TCL macros to point to the directories where the Borland and Tcl releases are installed. 3. Type "make". This will create a DLL called "example.dll" and a package index file called "pkgIndex.tcl". (c) If you are using the Visual C++ compilers: 1. You will need the file "vclibs41.zip" from the ftp.sunlabs.com:/pub/tcl archive. This file contains the .LIB import files needed to link against the binary release of Tcl 7.5. 2. Unzip the vclibs41.zip archive into the current directory. This should create the tcl75.lib and tk41.lib files. 3. Copy the file "makefile.vc" to the file "makefile". 4. Edit "makefle" and change the TOOLS32 and TCL variables to point to the directories where the Visual C++ and Tcl releases are installed. 5. Type "nmake". This will create a DLL called "example.dll" and a package index file called "pkgIndex.tcl". 6. Type "nmake test" to test the example. This will attempt to load the example package from the current directory. If it succeeds, you will see the message "Test passed.", otherwise you will see an error. (d) You can install the example by placing the "example.dll" file in the directory containing tclsh75.exe or a directory on your path. In addition, you should place the pkgIndex.tcl file into a directory on your auto_path. For Macintosh systems: Before you can compile the example, you must have the Tcl 7.5 source release. You can obtain the release by anonymous ftp from ftp.sunlabs.com:/pub/tcl/mac. You should install the directory including this example at the same level as the Tcl 7.5 workspace. Once you've done that, you should be able to use the included project file as is. Note: Dynamic loading only works on Power PC Macs. 3. Porting Issues ----------------- Because the binary release of Tcl for Windows is compiled with Borland C++ 4.52, the malloc() and free() routines it uses are not compatible with the malloc() and free() supplied by other C run time libraries (either VC++ or any other compiler). In order to avoid memory corruption, you must never pass malloc'ed memory to Tcl, expecting Tcl to use free() on it. Instead you need to pass your own free proc along with the data. This will mostly affect uses of Tcl_SetResult (or interp->result) and the TCL_DYNAMIC flag. Similarly, you should not attempt to free memory that Tcl has allocated. Eventually, we plan to supply a Tcl_Alloc and Tcl_Free routine that can be used by Tcl extensions to safely allocate/deallocate memory using the Tcl allocator, regardless of the compiler used.