cc -pthread -Wall -Wextra -Werror=implicit-function-declaration string/strlcat.c -o string/strlcat -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE -lm -lpthread -lrt -lcrypt -latomic string/strlcat.c: In function ‘main’: string/strlcat.c:11:25: error: implicit declaration of function ‘strlcat’; did you mean ‘strncat’? [-Werror=implicit-function-declaration] 11 | size_t result = strlcat(dst, src, 8); | ^~~~~~~ | strncat cc1: some warnings being treated as errors