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1. The three executables gawk, pgawk, and dgawk, have been merged into
one, named just gawk. As a result:
* The -R option is gone
* Use -D to run the debugger. An optional file argument is a
list of commands to run first.
* Use -o to do pretty-printing only.
* Use -p to do profiling.
This considerably reduces gawk's "footprint" and eases the documentation
burden as well.
2. Gawk now supports high precision arithmetic with MPFR. The default is
still double precision, but setting PREC changes things, or using
the -M / --bignum options. This support is not compiled in if the MPFR
library is not available.
3. The new -i option (from xgawk) is used for loading awk library files.
This differs from -f in that the first non-option argument is treated
as a script.
4. The new -l option (from xgawk) is used for loading dynamic extensions.
5. The dynamic extension interface has been completely redone! There is
now a defined API for C extensions to use. A C extension acts like
a function written in awk, except that it cannot do everything that awk
code can. However, this allows interfacing to any facility that is
available from C. This is a major development, see the doc, which has
a nice shiny new chapter describing everything.
This support is not compiled in if dynamic loading of shared libraries
is not supported.
The old extension mechanism is still supported for compatiblity, but
it will most definitely be removed at the next major release.
6. The "inplace" extension, built using the new facility, can be used to
simulate the GNU "sed -i" feature.
7. The and(), or() and xor() functions now take any number of arguments,
with a minimum of two.
8. New arrays: SYMTAB, FUNCTAB, and PROCINFO["identifiers"]. SYMTAB allows
indirect access to any defined variable or array; it is possible to
"walk" the symbol table, if that should be necessary.
9. Support for building gawk with a cross compiler has been improved.
10. Infrastructure upgrades: bison 2.7.1, gettext 0.18.2.1, automake 1.13.1,
libtool 2.4.2 for the extensions.
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