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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <string.h>
  4.  
  5. int test(char **output, int *output_len) {
  6.     int old_output_len;
  7.  
  8.     printf("\ninner before: %d\n", *output);
  9.  
  10.     // Add text first time
  11.     old_output_len = *output_len;
  12.     *output_len += 11;
  13.     printf("%d\t", *output_len);
  14.  
  15.     *output = realloc(*output, *output_len);
  16.     memset(*output + old_output_len, 0, 11);
  17.     *output = strcat(*output, "this is 11");
  18.     printf("%d\n", *output);
  19.  
  20.  /*
  21.     // Extend text
  22.     old_output_len = *output_len;
  23.     *output_len += 11;
  24.     printf("%d\t", *output_len * sizeof(char));
  25.  
  26.     // Ignore, now this doesn't get new pointer, unlike in previous code! but it still works though
  27.     &output = realloc(output, *output_len * sizeof(char));
  28.     memset(output + old_output_len, 0, 11);
  29.     *output = strcat(&output, "this is 11");
  30.     printf("%d\n", output);
  31.     printf("\ninner after: %d\n", output);*/
  32. }
  33.  
  34. int main() {
  35.     char *output = NULL;
  36.     int output_len = 0;
  37.  
  38.     printf("\nbefore: %d\n", &output);
  39.     test(&output, &output_len);
  40.     printf("\nafter:%d\n", &output);
  41.  
  42.     // This prints 0, wasn't output pointer updated by test?
  43.     printf("\n\n%d\n\n", output);
  44.     printf("%d\n", output_len);
  45.  
  46.     free(output);
  47.     //system("pause");
  48.  
  49.     return EXIT_SUCCESS;
  50. }
  51.  
Success #stdin #stdout 0s 2380KB
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stdin
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Standard input is empty
stdout
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before: -1073937240

inner before: 0
11	151134216

after:-1073937240


151134216

11
https://ideone.com/MoRbnr
language:
C (gcc 8.3)
created:
11 years ago
visibility:
secret

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