1. proc: error while loading shared libraries: libclntsh.so.11.1: cannot open shared object file: No such file or directory
解决方法：https://blog.csdn.net/roofwei/article/details/38946453
进入$ORACLE_HOME/lib文件夹，检查libclntsh是否存在
1>[oracle@oracledb lib]$ cd $ORACLE_HOME/lib
2>[oracle@oracledb lib]$ pwd
/opt/oracle/app/product/11.2.0/dbhome_1/lib
以root用户修改/etc/ld.so.conf添加$ORACLE_HOME/lib路径
3>[root@RHELDB tmp]# vi /etc/ld.so.conf，文件内容如下：
include ld.so.conf.d/*.conf
/opt/oracle/app/product/11.2.0/dbhome_1/lib #注：这里只能写绝对路径，不能写$ORACLE_HOME/lib
4>[root@RHELDB tmp]# ldconfig
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作者：roofwei
来源：CSDN
原文：https://blog.csdn.net/roofwei/article/details/38946453
版权声明：本文为博主原创文章，转载请附上博文链接！
2.Pro*C/C++: Release 11.2.0.1.0 - Production on Sun Apr 21 08:25:21 2019
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
System default option values taken from: /opt/oracle/app/product/11.2.0/dbhome_1/precomp/admin/pcscfg.cfg
Error at line 0, column 0 in file first.pc
PCC-F-02102, Fatal error while doing C preprocessing
解决方法：
https://www.linuxidc.com/Linux/2013-08/88880p2.htm
说明在 pcscfg.cfg 中系统头文件的位置不正确，需要重新设置:
查看pcscfg.cfg文件：
$[Oracle@oracleserver ~]$ cat /home/oracle/OraHome1/oracle10g/precomp/admin/pcscfg.cfg
sys_include=(/ade/aime_rdbms_9819/oracle/precomp/public,/usr/include,/usr/lib/gcc-lib/i486-SUSE-linux/2.95.3/include,/usr/lib/gcc-lib/i386-RedHat-linux/3.2.3/include,/usr/lib/gcc-lib/i386-redhat-linux7/2.96/include)
ltype=short
查找头文件 stddef.h 位置：
1》[root@oracleserver ~]# find / -name "stddef.h" -print
/usr/include/xulrunner-sdk-1.9/system_wrappers/stddef.h
/usr/include/linux/stddef.h
/usr/lib/bcc/include/stddef.h
/usr/lib/gcc/i386-redhat-linux/3.4.6/include/stddef.h
/usr/lib/gcc/i386-redhat-linux/4.1.1/include/stddef.h
/usr/lib/syslinux/com32/include/bitsize/stddef.h
/usr/lib/syslinux/com32/include/stddef.h
/usr/src/kernels/2.6.18-194.el5-i686/include/linux/stddef.h
比较发现，pcscfg.cfg中的/usr/lib/gcc-lib/i386-redhat-linux/3.2.3/include和/usr/lib/gcc-lib/i386-redhat-linux7/2.96/include路径均无效，与实际系统中的路径不符，修改为/usr/lib/gcc/i386-redhat-linux/4.1.1/include和/usr/lib/gcc/i386-redhat-linux/3.4.6/include 即可：
$ cat /home/oracle/OraHome1/oracle10g/precomp/admin/pcscfg.cfg
sys_include=(/ade/aime_rdbms_9819/oracle/precomp/public,/usr/include,/usr/lib/gcc-lib/i486-suse-linux/2.95.3/include,/usr/lib/gcc/i386-redhat-linux/4.1.1/include,/usr/lib/gcc/i386-redhat-linux/3.4.6/include)
ltype=short
写个简单的程序测试下：
$ proc test.pc
Pro*C/C++: Release 10.2.0.1.0 - Production on Tue May 21 16:07:16 2013
Copyright (c) 1982, 2005, Oracle. All rights reserved.
System default option values taken from: /home/oracle/OraHome1/oracle10g/precomp/admin/pcscfg.cfg
3。/usr/bin/ld: cannot find -lclntsh
/opt/oracle/app/product/11.2.0/dbhome_1/lib $ORACLE_HOME/
vi ~/.bashrc
xport LIBRARY_PATH=$LIBRARY_PATH:/opt/oracle/app/product/11.2.0/dbhome_1/lib:/usr/lib:.
登录数据库：
sqlplus system
Enter passwd:oracle
SQL>select * from emp;
关闭数据库：
shutdown immediate;
RHEL6.5系统管理中登录数据库的方法：
第一步：先以管理员身份登录oracle
sqlplus /nolog
SQL>conn sys as sysdba; 以系统管理员的身份连接
SQL> startup nomount; startup命令启动数据库实例
SQL>alter database mount; 挂载数据库
SQL>alter database open; alter database命令讲数据库的状态修改为open
第二步：以普通用户登录：
sqlplus system
passwd:oracle
关闭数据库：
SQL>shutdown immediate;
create table emp(
id number,
name varchar2(30),
salary number
);
插入数据库：
insert into emp values(1,'test1',123);
commit;
接下来编写程序
//first.pc C语言编写
/*
[oracle@oracledb]$ proc first.pc
[oracle@oracledb]$ gcc first.c -lclntsh
[oracle@oracledb$ ./a.out
*/
#include<stdio.h>
/* 包含一个数据结构 */
exec sql include sqlca;
int main()
{
char userpasswd[30]="system/oracle";
char var_name[30];
/* 链接数据库 */
exec sql connect:userpasswd;
/* 查询 */
exec sql select name into :var_name from emp where id=1;
printf("var_name=%s \n",var_name);
/* 提交之后断开链接 */
exec sql commit work release;
}
mycpp.pc C++ 语言编写
// proc ***.pc oname=***.cpp parse=none code=cpp;
// proc mycpp.pc oname=mycpp.cpp parse=none code=cpp
// g++ mycpp.cpp -lclntsh
// ./a.out
#include<iostream>
using namespace std;
/* 包含一个数据结构 */
exec sql include sqlca;
int main()
{
exec sql begin declare section;
char userpasswd[30]="system/oracle";
char var_name[30];
exec sql end declare section;
/* 链接数据库 */
exec sql connect:userpasswd;
/* 查询 */
exec sql select name into :var_name from emp where id=1;
cout<<"var_name="<<var_name<<endl;
/* 提交之后断开链接 */
exec sql commit work release;
}