The question is:

We defined “SOAM_RELEASE_BUILD” in environment as an Integer like

“set SOAM_RELEASE_BUILD=12345”

but in resource script, we need the string value of it like

VALUE "ProductVersion", VersionNumber ß a string here

So we defined the following macro in the resource script like

#define xstr(x) str(x)

#define str(x) #x

If you want to stringify the result of expansion of a macro argument, you have to use two levels of macros.

#define xstr(s) str(s)

#define str(s) #s

#define foo 4

str (foo)

     ==> "foo"

xstr (foo)

     ==> xstr (4)

     ==> str (4)

     ==> "4"

quoted from

http://www.ugcs.caltech.edu/info/gcc/cpp_3.html