How to compile reader.c and writer.c in the blog examples?

[Jerry Ajay]

Hi,

   When I use the naive `gcc writer.c` in the blog example at: https://pmem.io/2015/06/13/accessing-pmem.html . I get the underfined reference error:

/tmp/cc9pDRyw.o: In function `pmemobj_direct_inline':

writer.c:(.text+0x41): undefined reference to `_pobj_cached_pool'

writer.c:(.text+0x55): undefined reference to `_pobj_cache_invalidate'

writer.c:(.text+0x70): undefined reference to `_pobj_cache_invalidate'

writer.c:(.text+0x8a): undefined reference to `pmemobj_pool_by_oid'

/tmp/cc9pDRyw.o: In function `main':

writer.c:(.text+0x114): undefined reference to `pmemobj_create'

writer.c:(.text+0x146): undefined reference to `pmemobj_root'

writer.c:(.text+0x1ab): undefined reference to `pmemobj_persist'

writer.c:(.text+0x1ca): undefined reference to `pmemobj_memcpy_persist'

writer.c:(.text+0x1d6): undefined reference to `pmemobj_close'

collect2: error: ld returned 1 exit status

Similar situation with `gcc reader.c`:

/tmp/ccyyZuuB.o: In function `pmemobj_direct_inline':

reader.c:(.text+0x41): undefined reference to `_pobj_cached_pool'

reader.c:(.text+0x55): undefined reference to `_pobj_cache_invalidate'

reader.c:(.text+0x70): undefined reference to `_pobj_cache_invalidate'

reader.c:(.text+0x8a): undefined reference to `pmemobj_pool_by_oid'

/tmp/ccyyZuuB.o: In function `main':

reader.c:(.text+0xfc): undefined reference to `pmemobj_open'

reader.c:(.text+0x12b): undefined reference to `pmemobj_root'

reader.c:(.text+0x182): undefined reference to `pmemobj_close'

collect2: error: ld returned 1 exit status

The source code is exactly the same as shown in the blog example. 

How to resolve the loader error?

[Tony Mason]

At a minimum, you will want to link against the PMDK libraries that you're trying to use. 

Since these samples are in the PMDK, the easiest thing is probably just to look at how they build it. On my Fedora 31 system:

cc -c -o writer.o -std=gnu99 -ggdb -Wall -Werror -Wmissing-prototypes  -I../../../include -I. -I../../../examples  writer.c

LD_LIBRARY_PATH=/usr/lib64:/usr/lib64:/usr/lib64: cc -o writer writer.o -Wl,-rpath=../../../debug -L../../../debug  -lpmemobj -lpmem -pthread

cc -c -o reader.o -std=gnu99 -ggdb -Wall -Werror -Wmissing-prototypes  -I../../../include -I. -I../../../examples  reader.c

LD_LIBRARY_PATH=/usr/lib64:/usr/lib64:/usr/lib64: cc -o reader reader.o -Wl,-rpath=../../../debug -L../../../debug  -lpmemobj -lpmem -pthread

(pmdk/src/example/libpmemobj/string_store).

Tony

[Jerry Ajay]

Thank you.