[boost] [regex] unknown escape sequence in libs/regex/test/regress/test_perl_ex.cpp

From: Boris Gubenko (Boris.Gubenko_at_[hidden])
Date: 2008-01-13 17:53:02

  regex library tests regex_regress[_threaded] fail to compile on
  gcc-4.2.1_hpux_ia64 because for a character string

        "(?<=*|\B)"

  gcc 4.2.1 emits a hard error "unknown escape sequence". gcc 3.4 series
  issues a warning, as well as EDG-based compilers. See reproducer below.

  The character string in question should, probably, be: "(?<=*|\\B)".

  Ok to change?

  Thanks,
    Boris

x.cpp
-----
char s[] = "\B";

bash-2.03$ g++ --version | head -1 ; g++ -c x.cpp
g++ (GCC) 4.2.1
x.cpp:1: error: unknown escape sequence '\B'
bash-2.03$

bash-3.00$ g++ --version | head -1 ; g++ -c x.cpp
g++ (GCC) 3.4.6 20060404 (Red Hat 3.4.6-3)
x.cpp:1:12: warning: unknown escape sequence '\B'
bash-3.00$

bash-2.04$ eccp --version -c x.cpp
Edison Design Group C/C++ Front End, version 3.5 (Dec 20 2004 13:57:48)
Copyright 1988-2004 Edison Design Group, Inc.

"x.cpp", line 1: warning: unrecognized character escape sequence
  char s[] = "\B";

bash-2.04$