Date: Sat, 22 Aug 2009 10:22:40 +0400 From: Vladimir Prus <vladimir@codesourcery.com> To: boost-users@lists.boost.org Subject: Re: [Boost-users] Boost program_options Message-ID: <h6o2r1$j2f$1@ger.gmane.org> Content-Type: text/plain; charset=us-ascii Steve Nolen wrote:

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in program_options::parse_command_line - why can't the the argument "argv" be of type 'const charT*' rather than 'charT*'?

i ask because our unit tests were giving a bunch of errors because they were written like this..

vector< char* > cmdLine; cmdLine.push_back( "someExec" ); cmdLine.push_back( "--optflag1" ); cmdLine.push_back( "value1" ); etc.

then... char ** argv = &cmdLine[ 0 ];

then passing this to parse_command_line. when we compile under g++ 4.x we get warnings that assigning string literals to char* is a deprecated conversion. Actually I agree with the rationale, but this leaves me with a problem calling parse_command_line. Is it going to change any of these values?

No, it's not actually changing anything.

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I know the c standard calls for the argv in main's prototype to be non-const, but why can't parse_command_line be more restrictive?

Because it that case, you won't be able to pass main's argv to parse_command_line. - Volodya --------------------- ok why not? you would be passing a non-const (main::argv) to a const qualified parameter. this would just guarantee that the function couldn't modify it (which is what you're telling me is the case here). i thought this was allowed. -steve