Cygwin install does not have shared libraries, or how should I activate the shared libraries? - cygwin

Question

I'm new to Cygwin - so hopefully, someone can point me in the right direction. I would like to be able to choose to use the shared libraries to compile my code. However, so far, it seems that it always uses the static library, and I don't know where exactly I did wrong.
I installed Cygwin on my Windows 10 computer. Created a file: test.c, which contains:
#include <stdio.h>
const char msg[] = "Hello, world.";
int main(void){
puts (msg);
return 0;
}
I then compiled it with:
$ gcc -Wall -c test.c -o test.o
Then I checked the symbols using:
$ nm test.o
It gives me what I expected:
U __main
0000000000000000 T main
0000000000000000 R msg
U puts
where none of the symbols have been assigned addresses yet. This is all good.
Then, I linked it using the following:
$ gcc -Wall test.o –o test
Then checked the symbols like below:
$ nm test
I got the following:
0000000100401080 T main
0000000100401000 T mainCRTStartup
0000000100401640 T malloc
0000000100403000 R msg
0000000100401650 T posix_memalign
00000001004010d0 T puts
while I was expecting the symbol puts being something like
U puts##GLIBC_x.x.x`.
It seems like I did not have the shared libraries, or I'm not using the process correctly. What is wrong then? Thanks.

Answer 1

using objdump
objdump -x test.exe
DLL Name: cygwin1.dll
vma: Hint/Ord Member-Name Bound-To
813c 15 __cxa_atexit
814c 46 __main
8158 108 _dll_crt0
8164 115 _impure_ptr
8174 257 calloc
8180 373 cygwin_detach_dll
8194 375 cygwin_internal
81a8 403 dll_dllcrt0
81b8 579 free
81c0 909 malloc
81cc 1015 posix_memalign
81e0 1170 puts
81e8 1196 realloc
so puts is an external symbol taken from cygwin1.dll shared lib