undefined reference to <function name>
c, gcc, header-files
Solution
gcc -o testit teststack.c stack.c
You need to compile both C source files and link the object files; this does it all in one command.
Problem
I have this simple test file: ``` #include "stack.h" int main() { Stack* stck = init_stack(); return 0; } ``` and `stack.h` is defined as follows: ``` #ifndef STACK_H #define STACK_H #define EMPTY_STACK -1 typedef struct stack { char ch; struct stack* prev; } Stack; extern Stack* init_stack(); extern char pop(Stack*); extern void push(Stack*, char); #endif ``` These two files are in the same directory. But when I do `gcc ..` to build it, I keep getting the error below: ``` $ ls stack.c stack.h teststack.c $ gcc -o testit teststack.c /tmp/ccdUD3B7.o: In function `main': teststack.c:(.text+0xe): undefined reference to `init_stack' collect2: ld returned 1 exit status ``` Could anyone tell me what I did wrong here? Thanks,