https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106483
Bug ID: 106483
Summary: undefined reference to function implemented in shared
library if putting main.cpp after options, but non of
any error when putting before options
Product: gcc
Version: og10 (devel/omp/gcc-10)
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: xyang619 at 126 dot com
Target Milestone: ---
GCC version and OS: gcc version 10.2.1 20210110 (Debian 10.2.1-6)
Code example to reproduce the bugs:
#add.h
int add(int, int);
#add.cpp
#include "add.h"
int add(int a, int b) {
return a+b;
}
#main.cpp
#include "add.h"
#include <cstdio>
int main() {
int a=2;
int b=3;
int c=add(a,b);
printf("%d\n", c);
return 0;
}
#first, compile add.cpp to shared library, it works well
g++ -Wall -fPIC -shared -o libadd.so add.cpp
#second, compile main.cpp and link with the libadd.so, it will produce error as
followed:
g++ -Wall -L. -ladd -o add_main main.cpp
/usr/bin/ld: /tmp/ccCzqGbU.o: in function `main':
main.cpp:(.text+0x21): undefined reference to `add(int, int)'
collect2: error: ld returned 1 exit status
#however, if I put the main.cpp before the options, it works well
g++ main.cpp -Wall -L. -ladd -o add_main
