"undefined reference" error when linking in MinGW?

Question

MinGW

I made an object file from a C source file using MinGW.
When trying to link:
ld -o test.exe test.o
gives an error "undefined reference". For example, to printf.

Answer 1

The function code printfis in the library libmsvcrt.a. To be able to use printf, you need to link test.owith libmsvcrt.a. However, the matter is not limited to this, in order to at least run the program, a lot of auxiliary code is needed. The linker options might look something like this for a normal "hello world":

ld -LC:/MinGW/x64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/7.1.0
-LC:/MinGW/x64/mingw64/bin/../lib/gcc
-LC:/MinGW/x64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/7.1.0/../../../../x86_64-w64-mingw32/lib/../lib
-LC:/MinGW/x64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/7.1.0/../../../../lib
-LC:/MinGW/x64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/7.1.0/../../../../x86_64-w64-mingw32/lib
-LC:/MinGW/x64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/7.1.0/../../..
C:/MinGW/x64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/7.1.0/../../../../x86_64-w64-mingw32/lib/../lib/crt2.o
C:/MinGW/x64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/7.1.0/crtbegin.o
test.o
-lmingw32 -lgcc -lgcc_eh -lmoldname -lmingwex -lmsvcrt -lpthread -ladvapi32 -lshell32
-luser32 -lkernel32 -liconv -lmingw32 -lgcc -lgcc_eh -lmoldname -lmingwex -lmsvcrt
C:/MinGW/x64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/7.1.0/crtend.o