foo.c: In function 'main':
foo.c:4:9: warning: implicit declaration of function 'scanf_s'; did you mean 'scanf'? [-Wimplicit-function-declaration]
  int n; scanf_s("%d", &n);
         ^~~~~~~
         scanf
foo.c:6:2: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &a[0]);
  ^~~~~~~~~~~~~~~~~~
/tmp/ccKRhblB.o: In function `main':
foo.c:(.text.startup+0x36): undefined reference to `scanf_s'
foo.c:(.text.startup+0x79): undefined reference to `scanf_s'
collect2: error: ld returned 1 exit status

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