Function redeclaration on C++ -


i have been reviewing implementation of tool , observed unusual.

#ifdef __gnuc__ #define variable_is_not_used __attribute__ ((unused)) #else #define variable_is_not_used #endif     static variable_is_not_used void load_vertex_intervals(std::string base_filename, int nshards, std::vector<std::pair<vid_t, vid_t> > & intervals, bool allowfail);     static variable_is_not_used void load_vertex_intervals(std::string base_filename, int nshards, std::vector<std::pair<vid_t, vid_t> > & intervals, bool allowfail=false) {         std::string intervalsfilename = filename_intervals(base_filename, nshards);         std::ifstream intervalsf(intervalsfilename.c_str());          if (!intervalsf.good()) {             if (allowfail) return; // hack             logstream(log_error) << "could not load intervals-file: " << intervalsfilename << std::endl;         }         assert(intervalsf.good());          intervals.clear();          vid_t st=0, en;         for(int i=0; < nshards; i++) {             assert(!intervalsf.eof());             intervalsf >> en;             intervals.push_back(std::pair<vid_t,vid_t>(st, en));             st = en + 1;         }         for(int i=0; < nshards; i++) {             logstream(log_info) << "shard: " << intervals[i].first << " - " << intervals[i].second << std::endl;         }         intervalsf.close();     }

why declaration of function above implementation? use of this?

thanks in advance!

edit: posted code, instead of simplified example

the simplies example of when need use function lot of places:

static void fun(int x);  static void f() {     fun(5); }  static void fun(int x) {     cout<<"x = "<<x<<endl; }

without declaration not compile because in f()::fun(5) call compiler not know function exists. declaration says (afaik called "prototype") function exists , defined somewhere (will checked after).

without prototype compiler error:

t.cpp: in function ‘void f()’: t.cpp:20:10: error: ‘fun’ not declared in scope

upd: in code posted here declaration makes no sense @ all. in

static variable_is_not_used void load_vertex_intervals(std::string base_filename, int nshards, std::vector<std::pair<vid_t, vid_t> > & intervals, bool allowfail); static variable_is_not_used void load_vertex_intervals(std::string base_filename, int nshards, std::vector<std::pair<vid_t, vid_t> > & intervals, bool allowfail=false) {

you may delete first line declaration.


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