These `-m’ switches are supported in addition to the above on AMD x86-64 processors in 64-bit environments.
-m32
-m64
-mx32
Generate code for a 32-bit or 64-bit environment.
- The -m32 option sets int, long and pointer to 32 bits and generates code that runs on any i386 system.
- The -m64 option sets int to 32bits and long and pointer to 64 bits and generates code for AMD’s x86-64 architecture.
- The -mx32 option sets int, long and pointer to 32 bits and generates code for AMD’s x86-64 architecture.
For darwin only the -m64 option turns off the -fno-pic and -mdynamic-no-pic options.
因此在32位 linux make编译文件的时候 gcc -g -c 无需带-m32
在x86_64位linux make编译文件的时候 cc -m64 -g -c 是-m64必须带的。
可参考
http://blog.csdn.net/yyywill/article/details/54426900