Re: [Boost-users] Scoped Pairs of functions?

On Wed, Aug 17, 2011 at 10:49 AM, Brian Allison wrote:

  I'm on a project which uses a C++ compiler, but with a lot of C-isms. One of those is that there are objects with pairs of functions which allocate/deallocate resources. I don't have time to fix all of the design issues with the classes that do this (yet), but within one compilation unit I'd like to remove the chance for leaks.

  So - if I wanted to use boost types to wrap around 2 functions f() and g(), where each function

has a void or primitive return type takes zero or 1 argument where f() is called at some point in a scope, and then g() is called on exiting the scope from which f() is called and only if f() doesn't throw.. has its return value ignored. [Gahh....]

Is there a boost::bind (or lambda) expression that I can wrap in a type?

How do I generalize to include the possibility of a single argument?

The following works for me with gcc 4.0.1 (yeah, I know, old compiler): #include <iostream> #include #include void acquire_fixed() { std::cout << "Acquiring fixed resource\n"; } void release_fixed() { std::cout << "Releasing fixed resource\n"; } void acquire(const std::string& resource) { std::cout << "Acquiring " << resource << '\n'; } void release(const std::string& resource) { std::cout << "Releasing " << resource << '\n'; } class ScopedResource { public: typedef boost::function ResourceFunc; ScopedResource(const ResourceFunc& acq, const ResourceFunc& rel): mRelease(rel) { acq(); } virtual ~ScopedResource() { mRelease(); } private: ResourceFunc mRelease; }; int main(int argc, char *argv[]) { { ScopedResource fixed(acquire_fixed, release_fixed); std::cout << "during lifespan of 'fixed'\n"; } { ScopedResource something(boost::bind(acquire, "something"), boost::bind(release, "something")); std::cout << "during lifespan of 'something'\n"; } return 0; }