给出一个简单的hello world代码：

#include <stdio.h>
int main(void){
  puts("hello");
  return 0;
}

在64位alpine linux安装上,我尝试将其编译为64位和32位.
第一个工作正常,但第二个缺少32位库：

~ # gcc -Wall hello.c 
~ # gcc -Wall -m32 hello.c 
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../libssp_nonshared.a when searching for -lssp_nonshared
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible //usr/lib/libssp_nonshared.a when searching for -lssp_nonshared
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lssp_nonshared
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/libgcc.a when searching for -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../libgcc_s.so when searching for -lgcc_s
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible //usr/lib/libgcc_s.so when searching for -lgcc_s
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lgcc_s
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../libc.so when searching for -lc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../libc.a when searching for -lc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible //usr/lib/libc.so when searching for -lc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible //usr/lib/libc.a when searching for -lc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/libgcc.a when searching for -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../libgcc_s.so when searching for -lgcc_s
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible //usr/lib/libgcc_s.so when searching for -lgcc_s
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: cannot find -lgcc_s
collect2: error: ld returned 1 exit status

因为我没有找到解决这个问题的明显方法,所以我将32位版本的gcc,libgcc和musl-dev解​​压缩到本地目录并设置了LIBRARY_PATH：

~ # LIBRARY_PATH=usr/lib/gcc/i586-alpine-linux-musl/5.3.0:usr/lib gcc -Wall -m32 hello.c 
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/libgcc.a when searching for -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/libgcc.a when searching for -lgcc
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: i386:x86-64 architecture of input file `/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/crtbeginS.o' is incompatible with i386 output
/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/bin/ld: i386:x86-64 architecture of input file `/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/crtendS.o' is incompatible with i386 output
collect2: error: ld returned 1 exit status
~ # 

这部分修复了问题,但gcc仍然首先尝试64位库,并试图找到64位crt文件.

那么在alpine linux上编译32位二进制文​​件的正确方法是什么？

为了使最后一个问题更清楚,请看看：

~ # LIBRARY_PATH=/tmp gcc --verbose -Wall -m32 hello.c 2>&1|grep LIBRARY_PATH
LIBRARY_PATH=/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/:/tmp/:/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../../x86_64-alpine-linux-musl/lib/:/usr/lib/gcc/x86_64-alpine-linux-musl/5.3.0/../../../:/lib/:/usr/lib/

如果我只设置了一些LIBRARY_PATH,编译器会在内部添加其他目录.特别是它还预装了“错误的”系统目录,其中包含64位库.因此它使用了错误的crt libs,因此使用了上面的最后一个错误.

我要么需要正确的alpine包(而不关心它是如何工作的),要么我需要了解如何更改gcc内部添加的第一条路径.

最佳答案:

根据gcc -v对alpine gcc的编译没有multilib支持：

--disable-multilib

在debian上启用multilib时：

--with-multilib-list=m32,m64,mx32 --enable-multilib

需要Multilib支持才能使-m32可靠地工作.因此,alpine上的默认编译器实际上不适合编译32位二进制文​​件.