1 #ifndef PRINT_H 2 #define PRINT_H 3  4 #include 
      
        5 class ReplaceStdout 6 { 7 public: 8     ReplaceStdout(); 9     ~ReplaceStdout();10     bool isOK() { return _ok; }11 private:12     bool _ok;13 };14 void print(const char* format, ...);15 #endif
      

 

1 #include "print.h" 2 #include 
      
        3 #include 
       
         4  5 const static char* name = "/dev/null"; 6 static FILE* std_file = fopen(name, "w"); 7  8 bool replace() 9 {10     if (std_file) {11         fflush(stdout);12         std::swap(stdout->_fileno, std_file->_fileno);13         return true;14     }15     return false;16 }17 18 ReplaceStdout::ReplaceStdout():19     _ok(replace())20 {21 }22 23 ReplaceStdout::~ReplaceStdout()24 {25     replace();26 }27 28 void print(const char* format, ...)29 {30     va_list args;31     va_start(args, format);32     vfprintf(1 == stdout->_fileno ? stdout : std_file,33             format, args);34     va_end(args);35 }
       
      

 

1 #include "print.h" 2  3 int main(int argc, char* argv[]) 4 { 5     ReplaceStdout replace; 6     printf("printf hello\n"); 7     print("print hello\n"); 8     //{ ReplaceStdout replace; } 9     ReplaceStdout recover;10     printf("printf world\n");11     print("print world\n");12     return 0;13 }