Boost: How to use + in C POSIX regex interface
Boost: How to use + in C POSIX regex interface
I am trying to use BOOST.Regex POSIX Compatible C API's. I am using regcomp() to match an expression like a+, which should match aa and aaa, while using cflags=REG_BASIC. I have regcomp( reg, "a+", REG_BASIC) but it is not working.
regcomp()
a+
aa
aaa
cflags=REG_BASIC
regcomp( reg, "a+", REG_BASIC)
I found a link stating that + is not part of the POSIX standard. But I found in Boost POSIX Basic regular expression documentation an Emacs variation that supports + syntax.
+
+
How can I use + in POSIX Basic Regular Expressions? Or in other words, enable Emacs variation.
+
References:
+
{1,}
+
Well, if you plan to use
emacs "flavor", use boost::regex::emacs and enjoy +.– Wiktor Stribiżew
Jul 2 at 13:50
emacs
boost::regex::emacs
+
@WiktorStribiżew Actually I am using the POSIX Compatible C API's as the APIs are called from c code. Is there a way to use
boost::regex::emacs from c code?– Mohamed Elsayed
Jul 2 at 15:22
boost::regex::emacs
It seems you need
REG_EXTENDED rather than REG_BASIC then.– Wiktor Stribiżew
Jul 2 at 16:35
REG_EXTENDED
REG_BASIC
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You do not need the
+quantifier since you may use{1,}.+is an extension for some POSIX regex implementations (as in GNU sed), and is not portable.– Wiktor Stribiżew
Jul 2 at 13:37