在Sun OS上不能把文件名命名为ex.pc或ex.cpp

几天在Sun OS上编写测试程序，把一个文件命名为ex.pc, 发现编译出现如下的编译问题：

gcc -fPIC -D_XPG4_EXTENDED -D__unix -DHEADER_DES_LOCL_H -g -D_REENTRANT -I/us
r/local/include -L/usr/local/lib -L/usr/lib -I/usr/local/include/c++/3.4.6 -I.
-I/usr/local/include -I/program/netopt/share_src -I/usr/local/include -I/usr/i
nclude -L/usr/local/lib -L/usr/lib -L/usr/local/lib -I. -I/program/oracle/ora9
2/precomp/public -I/program/oracle/ora92/rebms/public -I/program/oracle/ora92/re
bms/demo -c ex.c
ex.c:117: error: syntax error before string constant
ex.c:125: error: syntax error before '}' token
ex.c:131: error: syntax error before string constant
In file included from ex.pc:5:
/usr/local/include/c++/3.4.6/iostream:44:28: bits/c++config.h: 无此文件或目录
In file included from /usr/local/include/c++/3.4.6/ios:44,
from /usr/local/include/c++/3.4.6/ostream:45,
from /usr/local/include/c++/3.4.6/iostream:45,
from ex.pc:5:
/usr/local/include/c++/3.4.6/iosfwd:46:29: bits/c++locale.h: 无此文件或目录
/usr/local/include/c++/3.4.6/iosfwd:47:25: bits/c++io.h: 无此文件或目录
In file included from /usr/local/include/c++/3.4.6/iosfwd:48,
from /usr/local/include/c++/3.4.6/ios:44,
from /usr/local/include/c++/3.4.6/ostream:45,
from /usr/local/include/c++/3.4.6/iostream:45,
from ex.pc:5:

弄了好长时间也没有发现问题所在，最后把文件改成其它的文件名，则编译通过，最后经过测试，命名为ex.cpp也会出现同样的

编译错误。

查了一下，才意识到ex时UNIX的编辑器，看来文件命名也需要注意很多问题。