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"Undefined link" error with shared library and ldflags

When I try to compile my code inside QEMU using make, I get an error undefined referenceduring the bind phase. Afaik settings are correct, so you need to use a shared library for the link library, but maybe I missed something.

Any help would be appreciated!

Below is a lot of additional information that I have already collected:

Solution: see Zach's answer

I managed to do this by adding LIBS+=-lcityto the file Makefile.target.

Thanks everyone!

Update:

make V=1 output:

cc -Werror -fPIE -DPIE -m64 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64
-D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wall -Wundef
-Wwrite-strings -Wmissing-prototypes -fno-strict-aliasing -I/home/user/cityhash
-Wendif-labels -Wmissing-include-dirs -Wempty-body -Wnested-externs
-Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers
-Wold-style-declaration -Wold-style-definition -Wtype-limits
-fstack-protector-all -I/usr/include/p11-kit-1     -I/usr/include/libpng12
-I/usr/include/pixman-1     -I../linux-headers -I..
-I/home/user/qemu/target-i386 -DNEED_CPU_H -I/home/user/qemu/include -pthread
-I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include   -O2
-D_FORTIFY_SOURCE=2 -g  -Wl,--warn-common -Wl,-z,relro -Wl,-z,now -pie -m64 -g
-L/home/user/lib -Wl,-rpath=/home/user/lib -lcity -o qemu-system-x86_64 [… all
*.o files … ] ../libqemuutil.a ../libqemustub.a   -lrt -pthread -lgthread-2.0
-lrt -lglib-2.0    -lutil -lrbd -lrados -lbluetooth   -lcurl   -lncurses -ltinfo
-lbrlapi  -luuid -lpng12   -ljpeg -lsasl2 -lgnutls   -lSDL   -lX11  -lz -laio
-lpixman-1   -lm

This is followed by the usual error output that I wrote below (with the exception of the LINKone that is missing in this case).

Mistake:

~/qemu$ make
...
  LINK  x86_64-softmmu/qemu-system-x86_64
my_code.o: In function `function`:
/home/user/qemu/my_code.c:982: undefined reference to `CityHash64'
...
collect2: error: ld returned 1 exit status
make[1]: *** [qemu-system-x86_64] Error 1
make: *** [subdir-x86_64-softmmu] Error 2

Settings:

./configure [...] \
    --extra-cflags='-I/home/user/cityhash' \
    --extra-ldflags='-L/home/user/lib -Wl,-rpath=/home/user/lib -lcity'

Folder structure:

~
β”œβ”€ cityhash/
β”‚  β”œβ”€ city.h
β”‚  └─ ...
β”œβ”€ lib/
β”‚  β”œβ”€ libcity.so
β”‚  └─ ...
└─ qemu/

Using the header and function (my_code.c):

[...]
 11  #include "city.h"

982  hash = CityHash64(buf, len);
[...]

Nm :

~/lib$ nm libcity.so
[...]
0000000000000fdc T CityHash64
[...]

Strace make:

~/qemu$ strace -f -o ../strace.out -- make
[...]
16111 stat("/home/user/lib/libcity.so", {st_mode=S_IFREG|0755, st_size=18468, ...}) = 0
16111 open("/home/user/lib/libcity.so", O_RDONLY) = 7
16111 fcntl(7, F_GETFD)                 = 0
16111 fcntl(7, F_SETFD, FD_CLOEXEC)     = 0
16111 fstat(7, {st_mode=S_IFREG|0755, st_size=18468, ...}) = 0
16111 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2aaaaaad9000
16111 lseek(7, 0, SEEK_SET)             = 0
16111 read(7, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`\7\0\0\0\0\0\0"..., 4096) = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 brk(0x2129000)                    = 0x2129000
16111 lseek(7, 12288, SEEK_SET)         = 12288
16111 read(7, "9\23\2%\25\0\2\4\1\364\0\2\4\1\2E\23\0\2\4\1\2>\23\0\2\4\1\203\0\2\4"..., 4096) = 4096
16111 lseek(7, 16384, SEEK_SET)         = 16384
16111 lseek(7, 16384, SEEK_SET)         = 16384
16111 lseek(7, 0, SEEK_SET)             = 0
16111 read(7, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`\7\0\0\0\0\0\0"..., 4096) = 4096
16111 lseek(7, 12288, SEEK_SET)         = 12288
16111 read(7, "9\23\2%\25\0\2\4\1\364\0\2\4\1\2E\23\0\2\4\1\2>\23\0\2\4\1\203\0\2\4"..., 4096) = 4096
16111 lseek(7, 0, SEEK_SET)             = 0
16111 read(7, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`\7\0\0\0\0\0\0"..., 4096) = 4096
16111 lseek(7, 8192, SEEK_SET)          = 8192
16111 read(7, "\6\2\233\f\7\10\0\0$\0\0\0\314\1\0\0\314\354\377\377\210\0\0\0\0A\16\20\206\2C\r"..., 4096) = 4096
16111 lseek(7, 12288, SEEK_SET)         = 12288
16111 lseek(7, 12288, SEEK_SET)         = 12288
16111 lseek(7, 12288, SEEK_SET)         = 12288
16111 lseek(7, 12288, SEEK_SET)         = 12288
16111 read(7, "9\23\2%\25\0\2\4\1\364\0\2\4\1\2E\23\0\2\4\1\2>\23\0\2\4\1\203\0\2\4"..., 4096) = 4096
16111 lseek(7, 8192, SEEK_SET)          = 8192
16111 read(7, "\6\2\233\f\7\10\0\0$\0\0\0\314\1\0\0\314\354\377\377\210\0\0\0\0A\16\20\206\2C\r"..., 4096) = 4096
16111 lseek(7, 0, SEEK_SET)             = 0
16111 read(7, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0`\7\0\0\0\0\0\0"..., 4096) = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
16111 lseek(7, 4096, SEEK_SET)          = 4096
[...]
16111 close(7)                          = 0
[...]
+4
1

, . :

-g -L/home/user/lib -Wl,-rpath=/home/user/lib -lcity -o qemu-system-x86_64 


[... all *.o files ...] ../libqemuutil.a ../libqemustub.a 
-lrt -pthread -lgthread2.0 [... more libraries ...]

, -lcity .o , : , .

, , Makefile, Automake, , -lcity LDADD , LDFLAGS. , --extra-libs=-lcity configure ( -lcity --extra-ldflags, , ). , make LDADD=-lcity. ( , LDADD), Makefile ( Makefile.am) , .

+1

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