【故障】
1. 從32位系統裏面複製過來的32位C或C++程序無法運行，提示找不到庫（比如libstdc++.so.6）
2. gcc或g++帶-m32選項編譯成32位的程序，提示失敗。例如：
[oct1158@oct1158-fedora clocktest]$ g++ p.cpp -m32 -o p
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-redhat-linux/8/libstdc++.so when searching for -lstdc++
/usr/bin/ld: cannot find -lstdc++
【解決方案】
安裝相同版本的i686平臺的libgcc和libstdc++。這裏所說的相同版本，是指和系統裏已有的x86_64平臺編譯器相同的版本。不相同的版本是不能共存的。
所以，安裝前，必須先將已有的64位libgcc和libstdc++升級到最新版本：
[oct1158@oct1158-fedora clocktest]$ sudo dnf upgrade libstdc++.x86_64
Last metadata expiration check: 0:06:54 ago on Fri 08 Mar 2019 14:01:57 CST.
Dependencies resolved.
================================================================================
Package Architecture Version Repository Size
================================================================================
Upgrading:
cpp x86_64 8.3.1-2.fc29 updates 10 M
gcc x86_64 8.3.1-2.fc29 updates 23 M
gcc-c++ x86_64 8.3.1-2.fc29 updates 12 M
gcc-gdb-plugin x86_64 8.3.1-2.fc29 updates 139 k
libgcc i686 8.3.1-2.fc29 updates 107 k
libgcc x86_64 8.3.1-2.fc29 updates 100 k
libgomp x86_64 8.3.1-2.fc29 updates 210 k
libstdc++ x86_64 8.3.1-2.fc29 updates 460 k
libstdc++-devel x86_64 8.3.1-2.fc29 updates 2.1 M
Transaction Summary
================================================================================
Upgrade 9 Packages
Total download size: 48 M
Is this ok [y/N]: y
Downloading Packages:
(1/9): gcc-8.3.1-2.fc29.x86_64.rpm 1.7 MB/s | 23 MB 00:13
(2/9): gcc-gdb-plugin-8.3.1-2.fc29.x86_64.rpm 114 kB/s | 139 kB 00:01
(3/9): libgcc-8.3.1-2.fc29.i686.rpm 708 kB/s | 107 kB 00:00
(4/9): libgcc-8.3.1-2.fc29.x86_64.rpm 658 kB/s | 100 kB 00:00
(5/9): libgomp-8.3.1-2.fc29.x86_64.rpm 839 kB/s | 210 kB 00:00
(6/9): libstdc++-8.3.1-2.fc29.x86_64.rpm 1.6 MB/s | 460 kB 00:00
(7/9): libstdc++-devel-8.3.1-2.fc29.x86_64.rpm 2.2 MB/s | 2.1 MB 00:00
(8/9): cpp-8.3.1-2.fc29.x86_64.rpm 286 kB/s | 10 MB 00:35
(9/9): gcc-c++-8.3.1-2.fc29.x86_64.rpm 319 kB/s | 12 MB 00:37
--------------------------------------------------------------------------------
Total 1.2 MB/s | 48 MB 00:40
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing : 1/1
Upgrading : libgcc-8.3.1-2.fc29.x86_64 1/18
Running scriptlet: libgcc-8.3.1-2.fc29.x86_64 1/18
Upgrading : libstdc++-8.3.1-2.fc29.x86_64 2/18
Running scriptlet: libstdc++-8.3.1-2.fc29.x86_64 2/18
Upgrading : libstdc++-devel-8.3.1-2.fc29.x86_64 3/18
Upgrading : libgomp-8.3.1-2.fc29.x86_64 4/18
Running scriptlet: libgomp-8.3.1-2.fc29.x86_64 4/18
Upgrading : cpp-8.3.1-2.fc29.x86_64 5/18
Running scriptlet: cpp-8.3.1-2.fc29.x86_64 5/18
Upgrading : gcc-8.3.1-2.fc29.x86_64 6/18
Running scriptlet: gcc-8.3.1-2.fc29.x86_64 6/18
Upgrading : gcc-c++-8.3.1-2.fc29.x86_64 7/18
Upgrading : gcc-gdb-plugin-8.3.1-2.fc29.x86_64 8/18
Running scriptlet: gcc-gdb-plugin-8.3.1-2.fc29.x86_64 8/18
Upgrading : libgcc-8.3.1-2.fc29.i686 9/18
Running scriptlet: libgcc-8.3.1-2.fc29.i686 9/18
Cleanup : gcc-gdb-plugin-8.2.1-6.fc29.x86_64 10/18
Running scriptlet: gcc-gdb-plugin-8.2.1-6.fc29.x86_64 10/18
Cleanup : gcc-c++-8.2.1-6.fc29.x86_64 11/18
Cleanup : libstdc++-devel-8.2.1-6.fc29.x86_64 12/18
Cleanup : libgcc-8.2.1-6.fc29.i686 13/18
Running scriptlet: libgcc-8.2.1-6.fc29.i686 13/18
Running scriptlet: gcc-8.2.1-6.fc29.x86_64 14/18
Cleanup : gcc-8.2.1-6.fc29.x86_64 14/18
Cleanup : libstdc++-8.2.1-6.fc29.x86_64 15/18
Running scriptlet: libstdc++-8.2.1-6.fc29.x86_64 15/18
Cleanup : libgcc-8.2.1-6.fc29.x86_64 16/18
Running scriptlet: libgcc-8.2.1-6.fc29.x86_64 16/18
Running scriptlet: cpp-8.2.1-6.fc29.x86_64 17/18
Cleanup : cpp-8.2.1-6.fc29.x86_64 17/18
Running scriptlet: libgomp-8.2.1-6.fc29.x86_64 18/18
Cleanup : libgomp-8.2.1-6.fc29.x86_64 18/18
Running scriptlet: libgomp-8.2.1-6.fc29.x86_64 18/18
Verifying : cpp-8.3.1-2.fc29.x86_64 1/18
Verifying : cpp-8.2.1-6.fc29.x86_64 2/18
Verifying : gcc-8.3.1-2.fc29.x86_64 3/18
Verifying : gcc-8.2.1-6.fc29.x86_64 4/18
Verifying : gcc-c++-8.3.1-2.fc29.x86_64 5/18
Verifying : gcc-c++-8.2.1-6.fc29.x86_64 6/18
Verifying : gcc-gdb-plugin-8.3.1-2.fc29.x86_64 7/18
Verifying : gcc-gdb-plugin-8.2.1-6.fc29.x86_64 8/18
Verifying : libgcc-8.3.1-2.fc29.i686 9/18
Verifying : libgcc-8.2.1-6.fc29.i686 10/18
Verifying : libgcc-8.3.1-2.fc29.x86_64 11/18
Verifying : libgcc-8.2.1-6.fc29.x86_64 12/18
Verifying : libgomp-8.3.1-2.fc29.x86_64 13/18
Verifying : libgomp-8.2.1-6.fc29.x86_64 14/18
Verifying : libstdc++-8.3.1-2.fc29.x86_64 15/18
Verifying : libstdc++-8.2.1-6.fc29.x86_64 16/18
Verifying : libstdc++-devel-8.3.1-2.fc29.x86_64 17/18
Verifying : libstdc++-devel-8.2.1-6.fc29.x86_64 18/18
Upgraded:
cpp-8.3.1-2.fc29.x86_64 gcc-8.3.1-2.fc29.x86_64
gcc-c++-8.3.1-2.fc29.x86_64 gcc-gdb-plugin-8.3.1-2.fc29.x86_64
libgcc-8.3.1-2.fc29.i686 libgcc-8.3.1-2.fc29.x86_64
libgomp-8.3.1-2.fc29.x86_64 libstdc++-8.3.1-2.fc29.x86_64
libstdc++-devel-8.3.1-2.fc29.x86_64
Complete!
[oct1158@oct1158-fedora clocktest]$
然後安裝glibc.i686：
[oct1158@oct1158-fedora clocktest]$ sudo dnf install glibc.i686
[sudo] password for oct1158:
Last metadata expiration check: 0:21:23 ago on Fri 08 Mar 2019 14:01:57 CST.
Package glibc-2.28-26.fc29.i686 is already installed.
Dependencies resolved.
Nothing to do.
Complete!
和libstdc++.i686：
[oct1158@oct1158-fedora clocktest]$ sudo dnf install libstdc++.i686
Last metadata expiration check: 0:08:24 ago on Fri 08 Mar 2019 14:01:57 CST.
Dependencies resolved.
================================================================================
Package Architecture Version Repository Size
================================================================================
Installing:
libstdc++ i686 8.3.1-2.fc29 updates 497 k
Transaction Summary
================================================================================
Install 1 Package
Total download size: 497 k
Installed size: 1.7 M
Is this ok [y/N]: y
Downloading Packages:
libstdc++-8.3.1-2.fc29.i686.rpm 254 kB/s | 497 kB 00:01
--------------------------------------------------------------------------------
Total 105 kB/s | 497 kB 00:04
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing : 1/1
Installing : libstdc++-8.3.1-2.fc29.i686 1/1
Running scriptlet: libstdc++-8.3.1-2.fc29.i686 1/1
Verifying : libstdc++-8.3.1-2.fc29.i686 1/1
Installed:
libstdc++-8.3.1-2.fc29.i686
Complete!
[oct1158@oct1158-fedora clocktest]$
可以用下面的命令查看已安裝的版本：
[oct1158@oct1158-fedora clocktest]$ sudo dnf install glibc libstdc++
Last metadata expiration check: 0:23:33 ago on Fri 08 Mar 2019 14:01:57 CST.
Package glibc-2.28-26.fc29.x86_64 is already installed.
Package glibc-2.28-26.fc29.i686 is already installed.
Package libstdc++-8.3.1-2.fc29.x86_64 is already installed.
Package libstdc++-8.3.1-2.fc29.i686 is already installed.
Dependencies resolved.
Nothing to do.
Complete!
[oct1158@oct1158-fedora clocktest]$
32位和64位的版本必須相同才能安裝，切記！
接下來，編譯一個C++程序測試一下：
#include <iostream>
using namespace std;
class A
{
private:
const char *p;
public:
A(const char *s);
void test(void);
};
A::A(const char *s) : p(s)
{
}
void A::test(void)
{
cout << p << endl;
}
int main(void)
{
A *a = new A("Hello World!");
a->test();
delete a;
return 0;
}
[oct1158@oct1158-fedora clocktest]$ g++ p.cpp -m32 -o p
[oct1158@oct1158-fedora clocktest]$ ./p
Hello World!
[oct1158@oct1158-fedora clocktest]$ file p
p: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux.so.2, for GNU/Linux 3.2.0, BuildID[sha1]=8cf224918f0a6259f5aea2411ec973a2234a1b02, not stripped
[oct1158@oct1158-fedora clocktest]$
這一次編譯就成功了
[oct1158@oct1158-fedora 4.9.1]$ ./cc1
./cc1: error while loading shared libraries: libz.so.1: cannot open shared object file: No such file or directory
找不到libz.so.1的問題也可以用同樣的方法解決。
[oct1158@oct1158-fedora 4.9.1]$ sudo dnf upgrade zlib
Last metadata expiration check: 0:04:39 ago on Fri 08 Mar 2019 14:34:16 CST.
Dependencies resolved.
Nothing to do.
Complete!
[oct1158@oct1158-fedora 4.9.1]$ sudo dnf install zlib.i686
Last metadata expiration check: 0:04:52 ago on Fri 08 Mar 2019 14:34:16 CST.
Dependencies resolved.
================================================================================
Package Architecture Version Repository Size
================================================================================
Installing:
zlib i686 1.2.11-14.fc29 fedora 91 k
Transaction Summary
================================================================================
Install 1 Package
Total download size: 91 k
Installed size: 201 k
Is this ok [y/N]: y
Downloading Packages:
zlib-1.2.11-14.fc29.i686.rpm 65 kB/s | 91 kB 00:01
--------------------------------------------------------------------------------
Total 23 kB/s | 91 kB 00:03
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing : 1/1
Installing : zlib-1.2.11-14.fc29.i686 1/1
Running scriptlet: zlib-1.2.11-14.fc29.i686 1/1
Verifying : zlib-1.2.11-14.fc29.i686 1/1
Installed:
zlib-1.2.11-14.fc29.i686
Complete!
[oct1158@oct1158-fedora 4.9.1]$ ./cc1
^C
[oct1158@oct1158-fedora 4.9.1]$
裝了zlib.i686就可以運行了cc1程序了。