Thread: confusion on linking files

Hello,

The following code just implements a dynamic array that is grown to double in size once its full. I do not understand why the reference cannot be resolved by the linker:

I have a file "memory.h" and "memory.c":

Code:

// memory.h
#ifndef clox_memory_h
#define clox_memory_h


#include "common.h"


#define GROW_CAPACITY(capacity) ((capacity) < 8 ? 8 : (capacity) * 2)


#define GROW_ARRAY(type, pointer, oldCount, newCount) \
    (type*)reallocate(pointer, sizeof(type) * (oldCount), \
        sizeof(type) * (newCount))


void* reallocate(void* pointer, size_t oldSize, size_t newSize);


#endif

Code:

// memory.c
#include <stdlib.h>

#include "memory.h"


void* reallocate(void* pointer, size_t oldSize, size_t newSize) {
  if (newSize == 0) {
    free(pointer);
    return NULL;
  }


  void* result = realloc(pointer, newSize);
  if (result == NULL){
    exit(1);
  }
  return result;
}

and the file that includes "memory.h" - "segment.c":

Code:

// segment.c where the linker cannot resolve reallocate() 
// in append_segment()
#include "segment.h"
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include "memory.h"


void init_segment(code_segment* segment)...


// the error originates here...
void append_segment(code_segment* segment, uint8_t byte){
    if (segment->count + 1 > segment->capacity){
        segment->code = GROW_ARRAY(uint8_t, segment->code,
            segment->capacity, GROW_CAPACITY(segment>capacity));
    }
    segment->code[segment->count] = byte;
    segment->count++;
    
}


void free_segment(code_segment* segment)...

this is the makefile and I dont understand why the linker cannot resolve
the reference to "reallocate()" in "append_segment()".

Code:

all: main test_segment segment.o


... (more targets)


segment.o: segment.c memory.c
    gcc -Wall -c segment.c -o segment.o


memory.o: memory.c
    gcc -Wall -c memory.c -o memory.o


... (more targets)

please ignore this, I refactored my code.

Code:

# Makefile

CFLAGS=-Wall
main: segment.o memory.o (more objects)

# Implicit rules
segment.o: segment.c segment.h memory.h
memory.o: memory.c memory.h

thanks! I have written a file with tests, "test_segment.c/h" and updated I have updated the Makefile. Every target " *.o" gets all its included headers as additional dependencies but my problem remains.
Is it correct to use a header file as requirement on multiple targets?
Or does the linker link methods multiple times and there is a name clash?

Thank you again for taking the time!

Code:

# Makefile
 
CFLAGS=-Wall
all: main test_segment


test_segment: test_segment.o debug.o segment.o
main: segment.o memory.o debug.o
 
# Implicit rules
test_segment.o: test_segment.c test_segment.h segment.h debug.h memory.h
segment.o: segment.c segment.h memory.h
memory.o: memory.c memory.h
debug.o: debug.c debug.h

Code:

//test_segment.h

#include "segment.h"


code_segment* build_test_segment();
void test_init_segment();
void test_append_segment();
void test_free_segment();
void fill_segment(uint8_t values[]);
void test_debug_file();

Code:

// test_segment.c
#include "test_segment.h"
#include "common.h"
#include "segment.h"
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include "debug.h"


implementation of the methods....




int main(int argc, char* argv[]){


    main code.....


    return 0;
}

and the "memory.c/h" file looks like this:

Code:

#ifndef memory_h
#define memory_h


#include "common.h"


#define GROW_CAPACITY(capacity) ((capacity) < 8 ? 8 : (capacity) * 2)


#define GROW_ARRAY(type, pointer, oldCount, newCount) \
    (type*)reallocate(pointer, sizeof(type) * (oldCount), \
        sizeof(type) * (newCount))


void* reallocate(void* pointer, size_t oldSize, size_t newSize);


#endif

Code:

#include <stdlib.h>


#include "memory.h"


void* reallocate(void* pointer, size_t oldSize, size_t newSize) {
  if (newSize == 0) {
    free(pointer);
    return NULL;
  }


  void* result = realloc(pointer, newSize);
  if (result == NULL){
    exit(1);
  }
  return result;
}

problem solved I did not include "memory.o"......