makefile在windows上使用cygwin，但不适用于ubuntu

Question

I have the following folder on my git repo - https://github.com/ryu577/base/tree/master/numerical/c/NumericalRecipiesCode/lib

On my windows machine which has cygwin installed, I can run make in that directory, which triggers the command -

gcc -o ../bin/lib/tst_libfns ../obj/nrutil.o ../obj/fileio.o ../obj/tst_libfns.o -I ../include -lm

This puts the tst_libfns.o and fileio.o in the obj directory.

Now, I pulled this repository into my ubuntu machine and tried the same thing. However, when the same command is generated there, it gives me the following error:

gcc -o ../bin/lib/tst_libfns ../obj/nrutil.o ../obj/fileio.o ../obj/tst_libfns.o -I../include -lm
../obj/fileio.o:fileio.c:(.text+0x52): undefined reference to `__getreent'
../obj/tst_libfns.o:tst_libfns.c:(.text+0x10): undefined reference to `__main'
collect2: error: ld returned 1 exit status
make: *** [../bin/lib/tst_libfns] Error 1

Am I missing something obvious?

Answer 1

I just figured it out. I had pulled in the .o files through git in the obj directory and gcc was somehow trying to use the existing files (which had been generated in Cygwin + Windows). Somehow, those .o files don't seem to be compatible with linux. When I delete them and run the make command again, the .o files are re-generated. I guess the moral of the story here is that binaries and executables generated by GCC in Windows are incompatible with Linux (and I'll guess vice versa).