/*
  Subversion doesn't make it easy to get the checkout 
  revision into an about box in the final build product.
  
  With GNU make, set a CPPFLAGS macro that gets the checkout rev number:
   CPPFLAGS = -DSVN_REVISION="`svnversion .`"
  
  Use the macro in the c code to set the rev number.
  
  Test this code with the following compile line:
  gcc -o svn_checkout_number svn_checkout_number.c -DSVN_REVISION=1234
*/

#include <stdio.h>

/*
   C Preprocessor has a special "#" operator that 
   you can use to turn things into strings, but it only 
   works in macros with variables.
   
   The macros with variables don't expand out my macro variable.
   so, I have two #defines for macros with variables,
   The first one expands out my macro variable. 
   The second one stringifies it.
   It's a common hack around this problem,
*/
#define STRINGIFY(x) STRINGIFY2(x) // 
#define STRINGIFY2(x) #x

int main(int argc, char** argv)
{
        const char* svn_revision = "$CheckoutRevision: " STRINGIFY(SVN_REVISION) "$";
        printf("%s\n", svn_revision);
        return 0;
}