prepare (1/3): 
finished

make (2/3): 
clang -std=gnu11 -O2 -Wall -Wextra -Werror -pedantic -Wno-unused-result -Wconversion -Wvla -o ex3 *.c
clang -std=gnu11 -O2 -Wall -Wextra -Werror -pedantic -Wno-unused-result -Wconversion -Wvla -fsanitize=address -fno-omit-frame-pointer -fsanitize=undefined -fsanitize=integer -o ex3_memory_check *.c
/tmp/main-0c6159.o: In function `main':
main.c:(.text+0xa8): undefined reference to `sort_file'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Makefile:13: recipe for target 'ex3' failed
make: *** [ex3] Error 1
make: *** Waiting for unfinished jobs....
/tmp/main-22a3cc.o: In function `main':
main.c:(.text+0x29c): undefined reference to `sort_file'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
Makefile:16: recipe for target 'ex3_memory_check' failed
make: *** [ex3_memory_check] Error 1

build failed