[cmake-developers] dependency scanning speed

[Tanner Lovelace]

On 9/11/06, Bill Hoffman <bill.hoffman at kitware.com> wrote:
> At 05:46 PM 9/10/2006, Alexander Neundorf wrote:
> >3) it uses std::string::resize(4*1024) to preallocate space for the strings,
> >and then assigns always c_str() instead of the std::string itself, since
> >assigning the std::string apparently throws away the preallocated memory so
> >that the memory has to be allocated again if the string grows (which it does
> >often when creating the key for the header location cache). This saves
> >another 4 seconds.
>
> This one concerns me.   Is this always legal to do?

My guess would be that it's implementation dependent.  A function
can be used as an lvalue when the return type is a reference, but
c_str()'s return type is a character pointer.  While many implementations
will certainly just return a pointer to the internal character representation
there's no guarantee that will happen or that the implementation won't
suddenly change at some point.

Cheers,
Tanner Lovelace
-- 
Tanner Lovelace
clubjuggler at gmail dot com
http://wtl.wayfarer.org/
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