changes

tcl是工具命令语言

232. 10/7/93 Eliminated dependency of tclMain.c on tclInt.h and
tclUnix.h, so that people can copy the file out of the Tcl source
directory to make modified private versions.

233. 10/8/93 Fixed bug in auto-loader that reversed the priority order
of entries in auto_path for new-style index files.  Now things are
back to the way they were before 3.0:  first in auto_path is always
highest priority.

234. 10/13/93 Fixed bug where Tcl_CommandComplete didn't recognize
comments and treat them as such.  Thus if you typed the line
    # {
interactively, Tcl would think that the command wasn't complete and
wait for more input before evaluating the script.

235. 10/14/93 Fixed bug where "regsub" didn't set the output variable
if the input string was empty.

236. 10/23/93 Fixed bug where Tcl_CreatePipeline didn't close off enough
file descriptors in child processes, causing children not to exit
properly in some cases.

237. 10/28/93 Changed "list" and "concat" commands not to generate
errors if given zero arguments, but instead to just return an empty
string.

----------------- Released version 7.1, 11/4/93 ------------------

Note: there is no 7.2 release.  It was flawed and was thus withdrawn
shortly after it was released.

238. 11/10/93 TclMain.c didn't compile on some systems because of
R_OK in call to "access".  Changed to eliminate call to "access".

----------------- Released version 7.3, 11/26/93 ------------------

239. 11/6/93 Modified "lindex", "linsert", "lrange", and "lreplace"
so that "end" can be specified as an index.

240. 11/6/93 Modified "append" and "lappend" to allow only two
words total (i.e., nothing to append) without generating an error.

241. 12/2/93 Changed to use EAGAIN as the errno for non-blocking
I/O instead of EWOULDBLOCK:  this should fix problem where non-blocking
I/O didn't work correctly on System-V systems.

242. 12/22/93 Fixed bug in expressions where cancelled evaluation
wasn't always working correctly (e.g. "set one 1; eval {1 || 1/$one}"
failed with a divide by zero error).

243. 1/6/94 Changed TCL_VOLATILE definition from -1 to the address of
a dummy procedure Tcl_Volatile, since -1 causes portability problems on
some machines (e.g., Crays).

244. 2/4/94 Added support for unary plus.

245. 2/17/94 Changed Tcl_RecordAndEval and "history" command to
call Tcl_GlobalEval instead of Tcl_Eval.  Otherwise, invocation of
these facilities in nested procedures can cause unwanted results.

246. 2/17/94 Fixed bug in tclExpr.c where an expression such as
"expr {"12398712938788234-1298379" != ""}" triggers an integer
overflow error for the number in quotes, even though it isn't really
a proper integer anyway.

247. 2/19/94 Added new procedure Tcl_DStringGetResult to move result
from interpreter to a dynamic string.

248. 2/19/94 Fixed bug in Tcl_DStringResult that caused it to overwrite
the contents of a static result in some situations.  This can cause
bizarre errors such as variables suddenly having empty values.

249. 2/21/94 Fixed bug in Tcl_AppendElement, Tcl_DStringAppendElement,
and the "lappend" command that caused improper omission of a separator
space in some cases.  For example, the script
    set x "abc{"; lappend x "def"
used to return the result "abc{def" instead of "abc{ def".

250. 3/3/94 Tcl_ConvertElement was outputting empty elements as \0 if
TCL_DONT_USE_BRACES was set.  This depends on old pre-7.0 meaning of
\0, which is no longer in effect, so it didn't really work.  Changed
to output empty elements as {} always.

251. 3/3/94 Renamed Tcl_DStringTrunc to Tcl_DStringSetLength and extended
it so that it can be used to lengthen a string as well as shorten it.
Tcl_DStringTrunc is defined as a macro for backward compatibility, but
it is deprecated.

252. 3/3/94 Added Tcl_AllowExceptions procedure.

253. 3/13/94 Fixed bug in Tcl_FormatCmd that could cause "format"
to mis-behave on 64-bit Big-Endian machines.

254. 3/13/94 Changed to use vfork instead of fork on systems where
vfork exists.

255. 3/23/94 Fixed bug in expressions where ?: didn't associate
right-to-left as they should.

256. 4/3/94 Fixed "exec" to flush any files used in >@ or >&@
redirection in exec, so that data buffered for them is written
before any new data added by the subprocess.

257. 4/3/94 Added "subst" command.

258. 5/20/94 The tclsh main program is now called Tcl_Main;  tclAppInit.c
has a "main" procedure that calls Tcl_Main.  This makes it easier to use
Tcl with C++ programs, which need their own main programs, and it also
allows an application to prefilter the argument list before calling
Tcl_Main.
*** POTENTIAL INCOMPATIBILITY ***

259. 6/6/94 Fixed bug in procedure returns where the errorInfo variable
could get truncated if an unset trace was invoked as part of returning
from the procedure.

260. 6/13/94 Added "wordstart" and "wordend" options to "string" command.

261. 6/27/94 Fixed bug in expressions where they didn't properly cancel
the evaluation of math functions in &&, ||, and ?:.

262. 7/11/94 Incorrect boolean values, like "ogle", weren't being
handled properly.

263. 7/15/94 Added Tcl_RegExpCompile, Tcl_RegExpExec, and Tcl_RegExpRange,
which provide lower-level access to regular expression pattern matching.

264. 7/22/94 Fixed bug in "glob" command where "glob -nocomplain ~bad_user"
would complain about a missing user.  Now it doesn't complain anymore.

265. 8/4/94 Fixed bug with linked variables where they didn't behave
correctly when accessed via upvars.

266. 8/17/94 Fixed bug in Tcl_EvalFile where it didn't clear interp->result.

267. 8/31/94 Modified "open" command so that errors in exec-ing
subprocesses are returned by the open immediately, rather than
being delayed until the "close" is executed.

268. 9/9/94 Modified "expr" command to generate errors for integer
overflow (includes addition, subtraction, negation, multiplication,
division).

269. 9/23/94 Modified "regsub" to return a count of the number of
matches and replacements, rather than 0/1.

279. 10/4/94 Added new features to "array" command:
    - added "get" and "set" commands for easy conversion between arrays
      and lists.
    - added "exists" command to see if a variable is an array, changed
      "names" and "size" commands to treat a non-existent array (or scalar
      variable) just like an empty one.
    - added pattern option to "names" command.

280. 10/6/94 Modified Tcl_SetVar2 so that read traces on variables get
called during append operations.

281. 10/20/94 Fixed bug in "read" command where reading from stdin
required two control-D's to stop the reading.

282. 11/3/94 Changed "expr" command to use longs for division just like
all other expr operators;  it previously used ints for division.

283. 11/4/94 Fixed bugs in "unknown" procedure:  it wasn't properly
handling exception returns from commands that were executed after
being auto-loaded.

----------------- Released version 7.4b1, 12/23/94 ------------------

284. 12/26/94 Fixed "install" target in Makefile (couldn't always
find install program).

285. 12/26/94 Added strcncasecmp procedure to compat directory.

286. 1/3/95 Fixed all procedure calls to explicitly cast arguments:
implicit conversions from prototypes (especially integer->double)
don't work when compiling under non-ANSI compilers.  Tcl is now clean
under gcc -Wconversion.

287. 1/4/95 Fixed problem in Tcl_ArrayCmd where same name was used for
both a label and a variable;  caused problems on several older compilers,
making array command misbehave and causing many errors in Tcl test suite.

----------------- Released version 7.4b2, 1/12/95 ------------------

288. 2/9/95 Modified Tcl_CreateCommand to return a token, and added
Tcl_GetCommandName procedure.  Together, these procedures make it possible
to track renames of a command.

289. 2/13/95 Fixed bug in expr where "089" was interpreted as a
floating-point number rather than a bogus octal number.
*** POTENTIAL INCOMPATIBILITY ***

290. 2/14/95 Added code to Tcl_GetInt and Tcl_GetDouble to check for
overflows when reading in numbers.

291. 2/18/95 Changed "array set" to stop after first error, rather than
continuing after error.

292. 2/20/95 Upgraded to use autoconf version 2.2.

293. 2/20/95 Fixed core dump that could occur in "scan" command if a
close bracket was omitted.

294. 2/27/95 Changed Makefile to always use install-sh for installations:
there's just too much variation among "install" system programs, which
makes installation flakey.

----------------- Released version 7.4b3, 3/24/95 ------------------

3/25/95 (bug fix) Changed "install" to "./install" in Makefile so that
"make install" will work even when "." isn't in the search path.

3/29/95 (bug fix) Fixed bug where the auto-loading mechanism wasn't
protecting the values of the errorCode and errorInfo variables.

3/29/95 (new feature) Added optional pattern argument to "parray" procedure.

3/29/95 (bug fix) Made the full functionality of
    "return -code ... -errorcode ..."
work not just inside procedures, but also in sourced files and at
top level.

4/6/95 (new feature) Added "pattern" option to "array names" command.

4/18/95 (bug fix) Fixed bug in parser where it didn't allow backslash-newline
immediately after an argument in braces or quotes.

4/19/95 (new feature) Added tcl_library variable, which application can
set to override default library directory.

4/30/95 (bug fix) During trace callbacks for array elements, the variable
name used in the original reference would be temporarily modified to
separate the array name and element name;  if the trace callback used
the same name string, it would get the wrong name (the array name without
element).  Fixed to restore the variable name before making trace
callbacks.

4/30/95 (new feature) Added -nobackslashes, -nocommands, and -novariables
switches to "subst" command.

5/4/95 (new feature) Added TCL_EVAL_GLOBAL flag to Tcl_RecordAndEval.

5/5/95 (bug fix)  Format command would overrun memory when printing
integers with very large precision, as in "format %.1000d 0".

5/5/95 (portability improvement) Changed to use BSDgettimeofday on
IRIX machines, to avoid compilation problems with the gettimeofday
declaration.

5/6/95 (bug fix) Changed manual entries to use the standard .TH
macro instead of a custom .HS macro;  the .HS macro confuses index
generators like makewhatis.

5/9/95 (bug fix) Modified configure script to check for Solaris bug
that makes vfork unreliable (core dumps result if vforked child
changes a signal handler);  will use fork instead of vfork if the
bug is present.

6/5/95 (bug fix) Modified "lsort" command to disallow recursive calls
to lsort from a comparison function.  This is needed because qsort
is not reentrant.

6/5/95 (bug fix) Undid change 243 above:  changed TCL_VOLATILE and
TCL_DYNAMIC back to integer constants rather than procedure addresses.
This was needed because procedure addresses can have multiple values
under some dynamic loading systems (e.g. SunOS 4.1 and Windows).

6/8/95 (feature change) Modified interface to Tcl_Main to pass in the
address of the application-specific initialization procedure.
Tcl_AppInit is no longer hardwired into Tcl_Main.  This is needed
in order to make Tcl a shared library. 

6/8/95 (feature change) Modified Makefile so that the installed versions
of tclsh and libtcl.a have version number in them (e.g. tclsh7.4 and
libtcl7.4.a) and the library directory name also has an embedded version
number (e.g., /usr/local/lib/tcl7.4).  This should make it easier for
Tcl 7.4 to coexist with earlier versions.

----------------- Released version 7.4b4, 6/16/95 ------------------

6/19/95 (bug fix) Fixed bugs in tclCkalloc.c that caused core dumps
if TCL_MEM_DEBUG was enabled on word-addressed machines such as Crays.

6/21/95 (feature removal) Removed overflow checks for integer arithmetic:
they just cause too much trouble (e.g. for random  number generators).

6/28/95 (new features) Added tcl_patchLevel and tcl_version variables,
for consistency with Tk.

6/29/95 (bug fix) Fixed problem in Tcl_Eval where it didn't record
the right termination character if a script ended with a comment.  This
caused erroneous output for the following command, among others:
puts "[
expr 1+1
# duh!
]"

6/29/95 (message change) Changed the error message for ECHILD slightly
to provide a hint about why the problem is occurring.

----------------- Released version 7.4, 7/1/95 ------------------

7/18/95 (bug fix) Changed "lreplace" so that nothing is deleted if
the last index is less than the first index or if the last index
is < 0.