Change-Log for MAWK


http://invisible-island.net/mawk/CHANGES
-- $MawkId: CHANGES,v 1.217 2014/09/14 22:36:13 tom Exp $

Changes by Thomas E Dickey <dickey@invisible-island.net>

20140914
        + rename vs6.mak / vs6.h to vs2008 for Visual Studio 2008 compiles.
        + remove MS-DOS support.
        + add a check in split for empty regex, treating that the same as an
          empty string (Original-Mawk #9).
        + correct inconsistently-ifdef'd reset of errno in check_strnum()
          function, which caused some values to be internally classified as
          strings rather than strnums (Original-Mawk #26).
        + add parameter to REmatch to control use of REG_NOTBOL and its
          equivalent in mawk (prompted by discussion with Mike Brennan,
          Original-Mawk #24).
        + settle on "gsub3" implementation (suggested by Mike Brennan,
          Original-Mawk #11).
        + change default for configure option --enable-init-srand to enable
          this (discussion with Mike Brennan).
        + add -W random option to set initial srand() seed.
        + add TraceVA, use to provide debug-traces for errmsg().
        + add note in manpage about "nextfile", see for example:
            http://www.opengroup.org/austin/docs/austin_578.txt
            http://austingroupbugs.net/view.php?id=607
        + make it possible to build with "bsd" library ported to Linux by
          setting LIBS=-lbsd before running configure script.
        + show random-function names in version message, as well as maximum
          integer-value.
        + modify initialization of srand default seed from time of day to use
          gettimeofday, etc., so that successive runs of mawk are less likely
          to use the same seed value (suggested by Mike Brennan).
        + make a further refinement, "gsub3" which uses a single pass.
        + change SType and SLen types to improve performance as well as
          handling larger regular expressions (suggested by Mike Brennan).
        + fix some minor issues reported by Coverity.
        + regenerate parse.c using byacc 20140422
        + modify makefile-rule for generating parse.c to keep the "#line"
          preprocessor lines consistent with the actual filename.  This is
          needed by lcov.
        + add test/reg7.awk to help with recent testing.
        + discard intermediate new_gsub used for regression-testing, will do
          further improvements based on "gsub2".
        + fix a comparison in rexp3.c to work with embedded nulls (patch by
          Mike Brennan).
        + in-progress changes to implement "gsub2", which will reduce copying.
        + discard intermediate old_gsub used for regression-testing, using
          original gsub function renamed to "gsub0" for that purpose.
        + remove old compiler information from version message.
        + remove NF value from version message.
        + patches by Mike Brennan:
          + changed the intermediate storage of STRINGS used by split.
          + cleaned up the xxx_split() functions.
            a) removed hand loop unrolling. What was an optimization for
            intel 8086/88 is silly today.
            b) consequence of a) some macros went away so the code is easier
            to read/understand.
            c) handles null in input string
               Note:  re_split() does \x00 null correctly, but it calls
               REmatch() which does not.  I have examples where REmatch works
               with nulls and examples of not working.  That needs to be fixed.
          + changed field allocation to support no upper limit.
        + when comparing two strings, allow for embedded nulls.
        + add checks in rexp3.c for infinite loop for testcase noloop.awk
          (report by Tibor Palinkas).
        + improve test-package for debian by adding postrm script to restore
          "mawk-base" to its unalternatized configuration, as well as adding
          messages to the other pre/post scripts.
        + patches by Mike Brennan:
          + increase some limits: NF is now 1048575, sprintf limit is 8192.
          + updated array.w; mostly documentation improvements
          + add array.pdf generated from array.w
        + add -Wu / -Wusage / -Wh / -Whelp to show usage message, like gawk.
          If long options are enabled, honor --help and --usage as well.
        + if no command-line parameters are given, show usage message like
          gawk and BWK (report by Michael Sanders).
        + improve configure macros CF_ADD_CFLAGS, CF_ADD_LIBS, CF_XOPEN_SOURCE,
          e.g., for Minix3.2 port.
        + restore in-progress change to gsub; resolved problem handling its
          internal use of vectors for second parameter when "&" marker is used.
        + improve configure check for Intel compiler warnings; trim unwanted
          -no-gcc option.
        + for Solaris suppress the followup check for defining _XOPEN_SOURCE
        + update config.guess and config.sub

20131226
        + add configure check to work around recent breakage in Cygwin's math.h
          which declares _LIB_VERSION without allowing it to be updated (report
          by Gert Hulselmans).
        + minor updates to configure script, for clang and mingw
        + update config.guess and config.sub

20130803
        + minor updates to configure script
        + add limit-checks, improve index computation in scan.c to fix old
          1.3.3 problems with very long string-literals in the parsed script
          (report by Marcin Krol).
        + update config.guess and config.sub

20130219
        + modify missing-operand check in rexp.c to allow the case of empty
          "()", matching behavior of gawk and BWK (report by Arkadiusz
          Miskiewicz).
        + revert in-progress change to gsub retain ifdef'd for additional
          development since it did not handle array as the second parameter
          (report by Arkadiusz Miskiewicz).

20121209
        + build-fix for cygwin in matherr.c, which declares a different type
          for _LIB_VERSION
        + add missing "-f" option in examples/gdecl.awk
        + fix a regression in fflush, ensuring that it returns an error if
          the argument does not match any output filename (report by Nathan
          Weeks).
        + modify wording of configure --help message to make it clear that
          the default for --with-builtin-regex uses the builtin regular
          expression engine of mawk.
        + fix issues reported by Coverity scan.  Most of these were minor,
          and were addressed by modifying the source to allow Coverity to
          improve its analysis of the code.
        + amend support for LC_NUMERIC by translating period to the local
          decimal separator as needed to work with strtod() which is used
          to validate decimal constants when scanning source files.  This
          fixes an infinite loop with
                mawk 'BEGIN { print 1.0 }'
          (report by Jan Psota).
        + regenerate man/mawk.doc, overlooked in previous updates.

20121129
        + change behavior if internal fflush call fails: rather than exiting
          with an error, propagate the return value to the script as -1, for
          consistency with gawk and BWK (discussion with Aharon Robbins and
          Nathan Weeks).
        + add special case for forward reference to a function using an array
          parameter, updating the function's parameter type so that the array
          is passed properly.
        + support length(array), as done in gawk and BWK awk (Original-Mawk #1).
        + support LC_NUMERIC, which will modify the displayed decimal point in
          some locales.  It does not modify the decimal point used for input,
          matching the behavior of nawk and BWK awk (prompted by request from
          Yechiel Bardov for thousands-separator).
        + add configure option --enable-init-srand to allow choice whether to
          initialize random numbers automatically at startup or not.  Not doing
          this makes programs more predictable (Debian #63843, Original-Mawk
          #3).
        + add configure option --enable-builtin-srand, use that to deprecate
          mawk's builtin srand/rand functions which generally are not as good
          as the system-provided functions.
        + extend --enable-trace configure option to show builtin functions.
        + add systime and mktime functions
        + when warning about unrecognized options, do not exit with error
          on these gawk options:
                  --lint
                  --lint-old
                  --posix
                  --re-interval
                  --traditional
        + integrate strtime function (patch by Dominic Letz, Original-Mawk #2).
        + correct logic for "/dev/stdin" special device (GenToo #424137,
          Original-Mawk #17).
        + updates for configure script macros:
          + modify configure script and makefile to support cross-compiles.
          + remove Turbo C++ and Zortech C++ makefiles.
          + remove obsolete function-checks: fmod, memcpy, strchr, strerror,
            strtod, vfprintf.
          + remove obsolete checks for some headers:  math.h, stdarg.h,
            stdlib.h, string.h time.h
          + support --datarootdir option.
          + add 3rd parameter to AC_DEFINE's to allow autoheader to run.
          + remove unused macros.
        + update config.guess and config.sub
        + add icons for webpage artwork

20120627
        + add "/dev/stdin" name for stdin for consistency with other
          implementations of awk (suggested by Aharon Robbins).
        + improve overflow check in check_strnum() (Ubuntu #485574).
        + implement gawk extension "nextfile" (suggested by Aharon Robbins).
        + updates for configure macros CF_ANSI_CC_CHECK, CF_ENABLE_TRACE,
          CF_GCC_ATTRIBUTES, CF_GCC_WARNINGS, CF_MAKE_TAGS, CF_MSG_LOG,
          CF_REGEX, CF_XOPEN_SOURCE.
        + update config.guess and config.sub

20101210
        + update copyright notices to reflect changes made starting 20080909.
          This commit was made in May 2012, updates only copyright notices
          needed for project registration on Savannah as discussed in Debian
          #554167.  However, since current policy on Savannah discriminates
          against GPLv2, it will be hosted elsewhere.  See
                http://invisible-island.net/mawk/
                http://github.com/ThomasDickey

20101207
        + add configure --enable-trace, to consolidate various debugging
          traces which were written to stderr.  This writes to Trace.out.
        + modify zmalloc.c to make it simpler to use the --disable-leaks
          configure script option to analyze memory leaks.  The memory pool
          which interferes with analysis can be disabled by defining
          DEBUG_ZMALLOC.
        + (IN-PROGRESS) convert gsub() function from recursive, to
          non-recursive to lessen use of program stack (Debian #158481).
        + escape some dashes in manpage, to work with groff.
        + change section for Debian package to "interpreters" (Debian #442071).
        + fix printable token value for SC_MATCH in scan.c (report by Heiner
          Marxen).

20100625
        + correct translation of octal and hex escapes for system regular
          expression library.
        + modify configure script to support --program-suffix, etc.
        + add Debian package scripts, for "mawk-cur".
        + add RPM spec-file.
        + move release- and patch-level values from version.c to patchlev.h
          to simplify packaging scripts.

20100618
        + correct translation of "^{" pattern for system regular expression
          library  (report by Elias Pipping).
        + fix sentence fragment in README (report by Elias Pipping).

20100507
        + cleanup gcc warnings for 64-bit platform, e.g., use size_t rather
          than unsigned, etc.
        + fix warnings from clang --analyze
        + update/improve configure script
          + modify CF_GCC_VERSION to ignore stderr, e.g., from c89 alias
          + modify CF_GCC_WARNINGS, moving -W and -Wall into the list to check,
            since c89 alias for gcc complains about these options.
          + add --disable-leaks and related options, for testing.
          + add lint rule to makefile.
          + add configure-check for ctags to work with pkgsrc.
        + amend change of array.w, fixes a regression in "delete" (report by
          Heiner Marxen).

20100419
        + modify split() to handle embedded nulls in the string to split, e.g.,
                BEGIN{s="a\0b"; print length(s); n = split(s,f,""); print n}
          (report by Morris Lee).

        + modify array.w to update table pointers in the special case where
          an array is known to have string-indices, but is later indexed via
          integers.  The problem occurs when the array grows large enough to
          rehash it, e.g.,
                BEGIN{a["n"];for(i=1;i<1000;++i)printf "%d\n", a[i]; }
          (report by Morris Lee).

        + increase size of reference-count for strings to unsigned.  It was an
          unsigned short, which prevented using arrays larger than 64k, e.g.,
                BEGIN{for(i = 1; i <= 65550; ++i){if(i >= 65534 && i<= 65537) print i; s[i] = "a"}; delete s;}
          (report by Morris Lee).

        + add special case for Solaris 10 (and up) to configure check
          CF_XOPEN_SOURCE

        + refactored configure check CF_REGEX

20100224
        + add a configure check for large files (report by Sean Kumar).

        + modify check in collect_RE() to show the actual limit value, e.g.,
          MIN_SPRINTF-2 used for built-in regular expressions.

        + increase MIN_SPRINTF, used as limit on regular-expression size, to
          match the MAX_SPLIT value, i.e., slightly more than doubling the size
          (report by Markus Gnam).

        + further modify makefile to build outside the source-tree.

        + modify makefile and mawktest to use relative path again, since the
          existing script did not work with openSUSE's build (patch by Guido
          Berhoerster).

        + fix makefile's .c.i rule, which lacked CPP definition.

        + update mawktest.bat script to more/less correspond with mawktest,
          for Win32 console except where echo command does not handle the
          required quoting syntax.

        + add vs6.mak, for Visual Studio 6.

        + modify mawktest script to report results from all tests, rather than
          halting on the first failure.

        + add limit-check after processing match(test, "[^0-9A-Za-z]") to
          ensure the internal trailing null of the test-string is not mistaken
          for part of the string, i.e., RSTART, RLENGTH are computed correctly
          (report by Markus Gnam).

        + modify parsing of -W option to use comma-separated values, e.g.,
          "-Wi,e" for "-Winteractive" and "-Werror".

        + add timestamp to scancode.c, to help manage revisions.

        + improve configure macro CF_XOPEN_SOURCE, making it remove possibly
          conflicting definitions before adding new ones.

        + update config.guess and config.sub

        > patches by Jan Psota:

        + improve buffering for -Winteractive option.

        + allow multiple single-character flags after -W, e.g., "-Wie" for
          "-Winteractive" and "-Werror" to permit these to be passed on a
          "#"-line of a shell script, e.g.,
                #!/usr/bin/mawk -Wie

        > patches by Jonathan Nieder:

        + add new M_SAVE_POS and M_2JC operation codes (states) to the
          built-in regular expression engine.  Use these to reimplement
          m* (closure), to provide a way to avoid infinite looping on
          matches against empty strings.  This change requires reimplementing
          the workaround for gawk's noloop1 testcase from 20090726.

        + improve buffer-overflow check for string_buff.

        + fix collect_RE to treat "[^]]" as a character class (meaning "not a
          closing bracket") but "[^^]]" not as one.  This also requires
          initializing the local "start of character class" variable to NULL
          rather than the beginning of the string, to avoid an invalid array
          access when collecting expressions such as "^text".

        + within a character class and not followed by a :, ., or ~, a "[" is
          just like any other character.  This way, you can tell mawk to scan
          for a literal [ character with "mawk /[[]/", and you can scan for a [
          or ] with "mawk /[][]/".  Also clean up the relevant loop in
          do_class() to make it a bit more readable.

        + outside a character class, a "]" is just like any other character.

        + prevent do_class() from scanning past the end, e.g., if the
          terminating zero byte was escaped.

        + fix regular-expression parsing when a right parenthesis ")" is
          found without a preceding left parenthesis.

        + fix resetting of position stack when backtracking.

        + modify regular-expression engine to avoid exponential running time
          for some regular expression matches in which the first match mawk
          finds extends to the end of the string.  This is a new fix for the
          gawk noloop2 test, added here for regression testing.

20091220
        + bump version to 1.3.4

        + update INSTALL and README files.

        + improve configure checks for math library.

          + change test for NaN to use sqrt() rather than log() to work around
            cygwin's partly broken math functions.

          + add/use isnanf() to work around other breakage in cygwin math
            functions.

          + add configure check for _XOPEN_SOURCE, etc., needed to define
            proper function pointer for sigaction, e.g., on Tru64.

          + add check for sigaction function pointer, whose POSIX form is
            absent from the cygwin header.

        + extend MAWKBINMODE, adding a third bit which when set will suppress
          the change for RS or ORS to use CR/LF rather than LF.  This is used
          for MinGW to make the "check" rule in a build work, for instance.

        + add configure check for functions used for pipe/system calls, e.g.,
          for MinGW where these are absent.

        + add runtime check for floating-point underflow exceptions

        + fix an old 1.3.3 bug in re_split(), which did not check properly for
          the end of buffer; this broke on Tru64.

        + drop obsolete config-user, v7 and atarist subdirectories

        + improve configure checks for sigaction, making the definitions used
          in fpe_check.c consistent with matherr.c

        + build fixes for AIX, Tru64.

        + add configure check for 'environ'.

        + remove redundant setlocale() calls; only LC_CTYPE and LC_NUMERIC
          are used.

20091213
        + add makedeps.sh script to aid in updating object dependencies in
          Makefile.in

        + use "mkdir -p" rather than mkdirs.sh (suggested by Aleksey Cheusov).

        + reformatted this file, to simplify extraction of contributor names.

        + update config.guess and config.sub

        > patches by Jonathan Nieder:

        + modify CF_DISABLE_ECHO autoconf macro to ensure that command lines
          in Makefile.in begin with a tab.

        + the makefile does not use $(MAKE); remove the SET_MAKE substitution.

        + add some files to the "make clean" rule, in case make gets
          interrupted in the middle of a rule.

        + add a maintainer-clean rule to the makefile, to remove files which
          could be regenerated.

        + fix an unescaped "-" in man/mawk.1

        + remove an unneeded cast in bi_funct.c

        + fix an unused parameter warning in matherr.c

        + drop unused line_no parameter from compile_error() and its callers.

        + convert makescan.c to ANSI C, do further cleanup of that file.

        + split-out scancode.h from scan.h

20090920
        + improve hash function by using FNV-1 algorithm (patch/analysis by
          Jim Mellander).  This greatly improves speed for accessing arrays
          with a large number of distinct keys; however the unsorted order in
          "for" loops will differ.

        + add "internal regex" or "external regex" string to version message to
          allow scripting based on support for embedded nulls.

        + drop obsolete CF_MAWK_PROG_GCC and CF_MAWK_PROG_YACC macros from
          configure script (report by Mike Frysinger).

        + fixes to allow build outside source-tree (report by Mike Frysinger).

        + correct logic in scan.c to handle expression "[[]" (report by Aleksey
          Cheusov).

        + add MAWK_LONG_OPTIONS feature to allow mawk to ignore long options
          which are not implemented.

        + two changes for embedded nulls, allows FS to be either a null or
          contain a character class with null, e.g., '\000' or '[ \000]':

          + modify built-in regular expression functions to accept embedded
            nulls.

          + modify input reader FINgets() to accept embedded nulls in data read
            from files.  Data read from standard input is line-buffered, and is
            still null-terminated.

        + update config.guess and config.sub

20090820
        + minor portability/standards fixes for examples/hical

        + add WHINY_USERS sorted-array feature, for compatibility with gawk
          (patch by Aharon Robbins).

        + correct lower-limit for d_to_U() function, which broke conversion of
          zero in "%x" format, added in fix for Debian #303825 (report by
          Masami Hiramatsu).

        + modify "%s" and "%c" formatting in printf/sprintf commands to ensure
          that "%02s" does not do zero-padding, for standards conformance
          (discussion with Aharon Robbins, Mike Brennan, prompted by Debian
          #339799).

20090728
        + add fallback definitions for GCC_NORETURN and GCC_UNUSED to build
          with non-gcc compilers (report by Jan Wells).

20090727
        + add check/fix to prevent gsub from recurring to modify on a substring
          of the current line when the regular expression is anchored to the
          beginning of the line; fixes gawk's anchgsub testcase.

        + add check for implicit concatenation mistaken for exponent; fixes
          gawk's hex testcase.

        + add character-classes to built-in regular expressions.

        + add 8-bit locale support

20090726
        + improve configure checks for MAX__UINT.

        + add a check for infinite loop in REmatch(), to work with gawk's
          noloop1 testcase.

        + modify logic to allow setting RS to an explicit null character, e.g.,
                RS="\0"
          (Ubuntu #400409).

        + modify workaround for (incorrect) scripts which use a zero-parameter
          for substr to ensure the overall length of the result stays the same.
          For example, from makewhatis:
                filename_no_gz = substr(filename, 0, RSTART - 1);

        + move regular-expression files into main directory to simplify
          building using configure --srcdir and VPATH.

        + modify internal functions for gsub() to handle a case from makewhatis
          script from man 1.6f which substitutes embedded zero bytes to a
          different value (report by Gabor Z Papp).

        + change default for configure --with-builtin-regex to prefer the
          builtin regular expressions.  They are incomplete, but POSIX regular
          expressions cannot match nulls embedded in strings.

        + require standard C compiler; converted to ANSI C.

        + rename #define'd SV_SIGINFO to MAWK_SV_SIGINFO to avoid predefined
          name on Mac OS X (report on comp.lang.awk).

        + revise configure script to use conventional scheme for generating
          config.h

20090721
        + port to cygwin, modifying test-script to work with executable-suffix
          and fp-exception code to allow const in declaration.

20090712
        + bump patch-date.

        + fix Debian #127293 "mawk does not understand unescaped '/' in
          character classes", noting that gawk 3.1.6 also has problems with
          this area.

        + drop support for varargs; use stdarg only.

        + add tags rule to makefile.

        + rename configure option "--with-local-regexp" to
          "--with-builtin-regex"

        + add build-fix from NetBSD port:  enable vax FP support when
          defined(__vax__) as well as BSD43_VAX.  from ragge.

        + add configure --disable-echo option

        + identify updated files with "MawkId" keywords, retaining old log
          comments for reference.  Ongoing changes are recorded here.

        + change maintainer email address to my own.

20090711
        + use conventional install/uninstall rules in makefile.

        + add install-sh script, mkdirs.sh, config.guess and config.sub

        + add $DESTDIR support to makefile

        + add uninstall make-target

        + add configure --enable-warnings option (fixed some warnings...)

        + change configure script to autoconf 2.52 to permit cross-compiles.

        + drop config.user file; replace with conventional autoconf --prefix,
          etc.

        + fill-in CA_REC.type in two places in parse.y which weren't
          initialized.

        + fix Debian #38353 (absent expression on last part of "for" statement
          caused core-dump).

        + fix Debian #303825 (printf %x clamps numbers to signed range rather
          than unsigned range).

        + apply fix from Debian #355966 (null-pointer check in
          is_string_split())

        + apply fix from Debian #391051 (limit-check in scan.c)

20090709
        + add support for external regexp libraries (patch by Aleksey Cheusov)
          (originally comp.lang.awk June 15 2005, also cited in Debian #355442
          March 6, 2006).

20090705
        + fixes to build on BeOS (if LIBS is set to -lroot), and QNX
          (redefinition of setmode).

20080909
        + fix gcc 4.3.1 -Wall warnings

        + transform mawk.ac.m4 to aclocal.m4, renaming macros to use "CF_" or
          "CF_MAWK_" prefixes depending on their reusability.  Modified macros
          to use quoting consistent with recent autoconf versions.

        + regenerate configure with autoconf version 2.13.20030927

        + regenerate parse.c with byacc - 1.9 20080827

        + ifdef'd prototypes in nstd.h which belong to stdlib.h, string.h to
          use standard C by default.

        + source-in Debian patches 01-08 (see below).  Changes for 20080909 fix
          Debian #496980 as well.

-------------------------------------------------------------------------------
Debian patches:

(Peter Eisentraut <petere@debian.org>  Sat, 05 Apr 2008 17:11:11 +0200)

08_fix-for-gcc3.3
        Debian #195371

(James Troup <james@nocrew.org>  Fri, 30 May 2003 15:24:50 +0100)

07_mawktest-check-devfull
        Debian #51875

06_parse.y-semicolons
        Debian #170973

05_-Wall-fixes

04_mawk.1-fix-pi
        Debian #103699

03_read-and-close-redefinition
        Debian #104124

02_fix-examples
        Debian #36011

01_error-on-full-fs
        Debian #28249
        Debian #4293

-------------------------------------------------------------------------------
1.3.1 -> 1.3.2 Sep 1996

1) Numeric but not integer indices caused core dump in new array scheme.
   Fixed bug and fired test division.

2) Added ferror() checks on writes.

3) Added some static storage specs to array.c to keep non-ansi
   compilers happy.

1.3 -> 1.3.1 Sep 1996
Release to new ftp site ftp://ftp.whidbey.net.

1) Workaround for overflow exception in strtod, sunos5.5 solaris.

2) []...] and [^]...] put ] in a class (or not in a class) without
   having to use back-slash escape.

1.2.2 -> 1.3 Jul 1996
Extensive redesign of array data structures to support large arrays and
fast access to arrays created with split.  Many of the ideas in the
new design were inspired by reading "The Design and Implementation of
Dynamic Hashing Sets and Tables in Icon" by William Griswold and
Gregg Townsend, SPE 23,351-367.

1.2.1 -> 1.2.2  Jan 1996

1) Improved autoconfig, in particular, fpe tests.  This is far from
   perfect and never will be until C standardizes an interface to ieee754.

2) Removed automatic error message on open failure for getline.

3) Flush all output before system().  Previous behavior was to only
   flush std{out,err}.

4) Explicitly fclose() all output on exit to work around AIX4.1 bug.

5) Fixed random number generator to work with longs larger than
   32bits.

6) Added a type Int which is int on real machines and long on dos machines.
   Believe that all implicit assumptions that int=32bits are now gone.

-------------------------------------------------------------------------------
Changes from version 1.1.4 to 1.2:

1) Limit on code size set by #define in sizes.h is gone.

2) A number of obscure bugs have been fixed such as,
   you can now make a recursive function call inside a for( i in A) loop.
   Function calls with array parameters in loop expressions sometimes
   generated erroneous internal code.

   See RCS log comments in code for details.

   Reported bugs are fixed.

3) new -W options


   -We file   :  reads commands from file and next argument, regardless
              of form, is ARGV[1].  Useful  for passing -v , -f etc to
              an awk program started with #!/.../mawk


      #!/usr/local/bin/mawk -We

      myprogram -v   works, while

      #!/usr/local/bin/mawk -f

      myprogram -v    gives error message
          mawk: option -v lacks argument

      This is really a posix bozo.  Posix says you end arguments with
      "--" , but this doesn't work with the "#!" convention.

   -W interactive :  forces stdout to be unbuffered and stdin to
        be line buffered.  Records from stdin are lines regardless of
        the value of RS.  Useful for interaction with a mawk on a pipe.

   -W dump, -Wd   :  disassembles internal code to stdout (used to be
       stderr) and exits 0.

4)  FS = "" causes each record to be broken into characters and placed
     into $1,$2 ...

     same with split(x,A,"") and split(x,A,//)

5)  print > "/dev/stdout"  writes to stdout, exactly the same as
    print

    This is useful for passing stdout to

    function my_special_output_routine(s, file)
    {
        # do something fancy with s
        print s > file
    }

6) New built-in function fflush() -- copied from the lastest att awk.

      fflush() : flushes stdout  and returns 0
      fflush(file)  flushes file and returns 0; if file was not an
      open output file then returns -1.

7)  delete  A ;  -- removes all elements of the array A

    intended to replace:

         for( i in A) delete A[i]

8)  mawk errors such as compilation failure, file open failure, etc.
    now exit 2 which reserves exit 1 for the user.

9)  No program now silently exits 0, prior behavior was to exit 2 with
    an error message