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  1. #include <stdbool.h>
  2. #include <stddef.h>
  3. #include <stdint.h>
  4. #include <stdio.h>
  5. #include <stdlib.h>
  6. #include <string.h>
  7. #include <time.h>
  8.  
  9. #define TIME_PRINTF(format, ...)    do {                        \
  10.     time_t t = time(NULL);                                      \
  11.     const char *prefix = "%s -> ";                              \
  12.     char time_format_vla[strlen(prefix) + strlen(format) + 1];  \
  13.     strcpy(time_format_vla, prefix);                            \
  14.     strcat(time_format_vla, format);                            \
  15.     printf(time_format_vla, ctime(&t), __VA_ARGS__);            \
  16. } while (false)
  17.  
  18. int main(void)
  19. {
  20.     srand(time(NULL));
  21.     TIME_PRINTF("Hello %s, your number is %d! Please wait...\n\n", "User", rand() % 100);
  22.  
  23.     // waste some time
  24.     for (size_t n=0; n < SIZE_MAX; ++n);
  25.  
  26.     // unfortunately, we need to pass at least two parameters    
  27.     TIME_PRINTF("%s", "So how's it going?");
  28. }
Success #stdin #stdout 12.66s 2424KB
comments (?)
stdin 
Standard input is empty
stdout 
Wed May 21 08:50:35 2014
 -> Hello User, your number is 28! Please wait...

Wed May 21 08:50:48 2014
 -> So how's it going?
https://ideone.com/77RO6a
测试可变参数宏
language:
C99 (gcc 8.3)
created:
11 years ago
visibility:
public

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