I have a question on how to use high gcc version to compile and get a lower gcc/glibc version compatible binary? The scenario is I built a binary on debian sid with its gcc-5.2 and some high glibc version, when I copy this binary to lower version debian system, it may not run or complain some library version info not available, like /lib/x86_64-linux-gnu/libtinfo.so.5: no version information available (required by /path/to/this-binary) this is dumped with `readelf -V ...` Version needs section '.gnu.version_r' contains 6 entries: Addr: 0x000000000042e770 Offset: 0x02e770 Link: 6 (.dynstr) 000000: Version: 1 File: librt.so.1 Cnt: 1 0x0010: Name: GLIBC_2.2.5 Flags: none Version: 13 0x0020: Version: 1 File: libdl.so.2 Cnt: 1 0x0030: Name: GLIBC_2.2.5 Flags: none Version: 9 0x0040: Version: 1 File: libtinfo.so.5 Cnt: 1 0x0050: Name: NCURSES_TINFO_5.0.19991023 Flags: none Version: 7 0x0060: Version: 1 File: libpthread.so.0 Cnt: 2 0x0070: Name: GLIBC_2.3.2 Flags: none Version: 5 0x0080: Name: GLIBC_2.2.5 Flags: none Version: 4 0x0090: Version: 1 File: libc.so.6 Cnt: 6 0x00a0: Name: GLIBC_2.14 Flags: none Version: 12 0x00b0: Name: GLIBC_2.10 Flags: none Version: 11 0x00c0: Name: GLIBC_2.3.4 Flags: none Version: 10 0x00d0: Name: GLIBC_2.3 Flags: none Version: 8 0x00e0: Name: GLIBC_2.3.2 Flags: none Version: 6 0x00f0: Name: GLIBC_2.2.5 Flags: none Version: 3 0x0100: Version: 1 File: libm.so.6 Cnt: 1 0x0110: Name: GLIBC_2.2.5 Flags: none Version: 2 I think the problem here is actually with library dependency, when built on debian sid higher version of glibc, it generates some version info in the '.gnu.version_r' section that caused unable to load on a lower version of debian; But I wonder does gcc have an option to support such need? in above case, with what gcc option can I build a binary without linking to GLIBC_2.14 ? and without NCURSES_TINFO_5.0.19991023? I found those are the two library symbols missing on my target system, or where I want to run this binary; the workaround is to use a lower debian version (same as the target) as the development system, but what if I want the better generated code by gcc-5.2 ? it's also against the encouragement for people to upgrade and test new compiler; one solution may be to compile a gcc-5.2 with target system lower glibc version, while most people still like to use a distro default compiler I think, may not have ability or do not want the burden to maintain a customized gcc/glibc sysroot; So does gcc support such requirement to build a binary without linking symbols higher than a specific lib version? If not, can we request such a feature? I have looked up some documentation did some online research, haven't found a simple answer yet, http://stackoverflow.com/a/2858996/5672998 has shown a .symver based solution, but its using __asm__ instructions is really inconvenient Thanks, - Derek
