Can't compile against OCILIB
I'm having trouble compiling some code against ocilib (libocilib.a) on version 3.9.0:
$ ls
libocilib.a ocilib.h test.c$ gcc -o test -L. -locilib test.c
/tmp/cc4071VP.o: In function `main': test.c:(.text+0x27): undefined reference to OCI_Initialize test.c:(.text+0x64): undefined reference to OCI_ConnectionCreate test.c:(.text+0x9d): undefined reference to OCI_StatementCreate test.c:(.text+0xaf): undefined reference to OCI_ExecuteStmt test.c:(.text+0xb8): undefined reference to OCI_GetResultset test.c:(.text+0xcc): undefined reference to OCI_GetString test.c:(.text+0xdd): undefined reference to OCI_FetchNext test.c:(.text+0xe6): undefined reference to OCI_Cleanup collect2: ld returned 1 exit status
Ok. In that case:
$ strings libocilib.a | grep OCI_Initialize
OCI_Initialize OCI_Initialize OCI_Initialize OCI_Initialize
There was a solution to this problem answered by the man (vince) himself on another page, but it isn't working for me.
What DOES work is when I try to compile against an .so:
$ ls
libocilib.so* libocilib.so.3* libocilib.so.3.9.0* ocilib.h test.c$ gcc -o test -L. -locilib test.c
$
The program runs as expected as well (after modifying LD_LIBRARY_PATH, of course!).
The solution mentioned earlier includes some defines -DOCI_IMPORT_LINKAGE
and -DOCI_CHARSET_ANSI
I've tried with both of these (even though the online docs say that DOCI_IMPORT_LINKAGE is only used while compiling the library itself. I had assumed that pertains more to the linki开发者_运维技巧ng of the actual oracle libs than it does ocilib. It was tried, none the less.
Speaking of which, if it helps to answer the question, I compiled the library to have runtime linking, having passed the --with-oracle-import=runtime
flag into ./configure.
One more side note, something similar happens on Windows 32-bit. No problems with Windows 64. I can link and run a program against my own compiled libocilib.lib just fine.
Hopefully I've provided enough clues... anyone know what I'm doing wrong?
Thanks in advance help.Have you tried linking it like this?
gcc -o test test.c -L. -locilib
At least in the past (I haven't done much C/C++ in a long time) the order of linking mattered.
test.o
would have references to OCI_Initialize
and with libocilib.a after test.o
, those would be satisfied. But if you linked the other way around those references would not be satisfied because the linker saw the OCI_Initialize
symbol before it looked at test.o
and so never realized it needed to keep a "pointer" to the symbol around when looking at test.o
.
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