foo.c: In function 'main':
foo.c:9:9: warning: 'gets' is deprecated [-Wdeprecated-declarations]
    9 |         gets(A);
      |         ^~~~
In file included from foo.c:1:
/nix/store/linb70pgp53f0kygxm5wk163dx22d681-glibc-2.37-45-dev/include/stdio.h:605:14: note: declared here
  605 | extern char *gets (char *__s) __wur __attribute_deprecated__;
      |              ^~~~
foo.c:10:9: warning: 'gets' is deprecated [-Wdeprecated-declarations]
   10 |         gets(B);
      |         ^~~~
/nix/store/linb70pgp53f0kygxm5wk163dx22d681-glibc-2.37-45-dev/include/stdio.h:605:14: note: declared here
  605 | extern char *gets (char *__s) __wur __attribute_deprecated__;
      |              ^~~~
foo.c:13:17: warning: implicit declaration of function 'strcat_s'; did you mean 'strcat'? [-Wimplicit-function-declaration]
   13 |                 strcat_s(B, A);
      |                 ^~~~~~~~
      |                 strcat
/nix/store/3r87a2wq1w4l66wnsm7rqvy608mx23h6-binutils-2.40/bin/ld: /tmp/ccJ9YKn7.o: in function `main':
foo.c:(.text.startup+0x1f): warning: the `gets' function is dangerous and should not be used.
/nix/store/3r87a2wq1w4l66wnsm7rqvy608mx23h6-binutils-2.40/bin/ld: foo.c:(.text.startup+0x53): undefined reference to `strcat_s'
/nix/store/3r87a2wq1w4l66wnsm7rqvy608mx23h6-binutils-2.40/bin/ld: foo.c:(.text.startup+0x67): undefined reference to `strcat_s'
collect2: error: ld returned 1 exit status

[Hydro](https://hydro.ac)提供评测服务