问一下关于g++的两个参数

enrico

－DHAVA_NAMESPACE_STD和-DDLLIMPORT

当我输入下面的命令的时候可以编译通过：

1. g++  -DHAVE_NAMESPACE_STD  -DDLLIMPORT="" -I/usr/local/pgsql/include -o cpptest cpptest.cc -L/usr/local/pgsql/lib -lpq++

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如果把-DHAVE_NAMESPACE_STD和-DDLLIMPORT=""去掉(或去掉任何一个)就会出现如下错误：

1. 
   
2. In file included from /usr/local/pgsql/include/libpq++.h:30,
   
3.                  from cpptest.cc:2:
   
4. /usr/local/pgsql/include/libpq++/pgconnection.h:49: syntax error before `{'
   
5.    token
   
6. /usr/local/pgsql/include/libpq++/pgconnection.h:55: syntax error before `public
   
7.    '
   
8. /usr/local/pgsql/include/libpq++/pgconnection.h:57: destructors must be member
   
9.    functions
   
10. /usr/local/pgsql/include/libpq++/pgconnection.h:57: virtual outside class
    
11.    declaration
    
12. /usr/local/pgsql/include/libpq++/pgconnection.h:60: non-member function `
    
13.    ConnStatusType Status()' cannot have `const' method qualifier
    
14. /usr/local/pgsql/include/libpq++/pgconnection.h:61: non-member function `bool
    
15.    ConnectionBad()' cannot have `const' method qualifier
    
16. /usr/local/pgsql/include/libpq++/pgconnection.h:62: non-member function `const
    
17.    char* ErrorMessage()' cannot have `const' method qualifier
    
18. /usr/local/pgsql/include/libpq++/pgconnection.h:65: non-member function `const
    
19.    char* DBName()' cannot have `const' method qualifier
    
20. /usr/local/pgsql/include/libpq++/pgconnection.h:76: syntax error before `
    
21.    protected'
    
22. /usr/local/pgsql/include/libpq++/pgconnection.h:79: syntax error before `('
    
23.    token
    
24. /usr/local/pgsql/include/libpq++/pgconnection.h:81: ISO C++ forbids declaration
    
25.    of `PgConnection' with no type
    
26. /usr/local/pgsql/include/libpq++/pgconnection.h:81: new declaration `int
    
27.    PgConnection()'
    
28. /usr/local/pgsql/include/libpq++/pgconnection.h:57: ambiguates old declaration
    
29.    `void PgConnection()'
    
30. /usr/local/pgsql/include/libpq++/pgconnection.h:83: syntax error before `
    
31.    private'
    
32. /usr/local/pgsql/include/libpq++/pgconnection.h:87: syntax error before `&'
    
33.    token
    
34. In file included from /usr/local/pgsql/include/libpq++.h:31,
    
35.                  from cpptest.cc:2:
    
36. /usr/local/pgsql/include/libpq++/pgdatabase.h:37: syntax error before `:' token
    
37. /usr/local/pgsql/include/libpq++/pgdatabase.h:45: destructors must be member
    
38.    functions
    
39. /usr/local/pgsql/include/libpq++/pgdatabase.h:51: non-member function `
    
40.    size_type Tuples()' cannot have `const' method qualifier
    
41. /usr/local/pgsql/include/libpq++/pgdatabase.h:52: non-member function `
    
42.    size_type CmdTuples()' cannot have `const' method qualifier
    
43. /usr/local/pgsql/include/libpq++/pgdatabase.h:54: non-member function `const
    
44.    char* FieldName(int)' cannot have `const' method qualifier
    
45. /usr/local/pgsql/include/libpq++/pgdatabase.h:55: non-member function `int
    
46.    FieldNum(const char*)' cannot have `const' method qualifier
    
47. /usr/local/pgsql/include/libpq++/pgdatabase.h:56: non-member function `Oid
    
48.    FieldType(int)' cannot have `const' method qualifier
    
49. /usr/local/pgsql/include/libpq++/pgdatabase.h:57: non-member function `Oid
    
50.    FieldType(const char*)' cannot have `const' method qualifier
    
51. /usr/local/pgsql/include/libpq++/pgdatabase.h:58: non-member function `int
    
52.    FieldSize(int)' cannot have `const' method qualifier
    
53. /usr/local/pgsql/include/libpq++/pgdatabase.h:59: non-member function `int
    
54.    FieldSize(const char*)' cannot have `const' method qualifier
    
55. /usr/local/pgsql/include/libpq++/pgdatabase.h:60: non-member function `const
    
56.    char* GetValue(int, int)' cannot have `const' method qualifier
    
57. /usr/local/pgsql/include/libpq++/pgdatabase.h:61: non-member function `const
    
58.    char* GetValue(int, const char*)' cannot have `const' method qualifier
    
59. /usr/local/pgsql/include/libpq++/pgdatabase.h:62: non-member function `bool
    
60.    GetIsNull(int, int)' cannot have `const' method qualifier
    
61. /usr/local/pgsql/include/libpq++/pgdatabase.h:63: non-member function `bool
    
62.    GetIsNull(int, const char*)' cannot have `const' method qualifier
    
63. /usr/local/pgsql/include/libpq++/pgdatabase.h:64: non-member function `int
    
64.    GetLength(int, int)' cannot have `const' method qualifier
    
65. /usr/local/pgsql/include/libpq++/pgdatabase.h:65: non-member function `int
    
66.    GetLength(int, const char*)' cannot have `const' method qualifier
    
67. /usr/local/pgsql/include/libpq++/pgdatabase.h:69: non-member function `void
    
68.    DisplayTuples(FILE*, bool, const char*, bool, bool)' cannot have `const'
    
69.    method qualifier
    
70. /usr/local/pgsql/include/libpq++/pgdatabase.h:71: non-member function `void
    
71.    PrintTuples(FILE*, bool, bool, bool)' cannot have `const' method qualifier
    
72. /usr/local/pgsql/include/libpq++/pgdatabase.h:76: non-member function `const
    
73.    char* OidStatus()' cannot have `const' method qualifier
    
74. /usr/local/pgsql/include/libpq++/pgdatabase.h:79: syntax error before `
    
75.    protected'
    
76. /usr/local/pgsql/include/libpq++/pgdatabase.h:88: syntax error before `&' token
    
77. In file included from /usr/local/pgsql/include/libpq++.h:32,
    
78.                  from cpptest.cc:2:
    
79. /usr/local/pgsql/include/libpq++/pglobject.h:38: syntax error before `:' token
    
80. /usr/local/pgsql/include/libpq++/pglobject.h:43: 'string' is used as a type,
    
81.    but is not defined as a type.
    
82. /usr/local/pgsql/include/libpq++/pglobject.h:46: syntax error before `public'
    
83. /usr/local/pgsql/include/libpq++/pglobject.h:48: ISO C++ forbids declaration of
    
84.    `PgLargeObject' with no type
    
85. /usr/local/pgsql/include/libpq++/pglobject.h:48: only declarations of
    
86.    constructors can be `explicit'
    
87. /usr/local/pgsql/include/libpq++/pglobject.h:49: destructors must be member
    
88.    functions
    
89. /usr/local/pgsql/include/libpq++/pglobject.h:57: non-member function `int
    
90.    Tell()' cannot have `const' method qualifier
    
91. /usr/local/pgsql/include/libpq++/pglobject.h:62: syntax error before `)' token
    
92. /usr/local/pgsql/include/libpq++/pglobject.h:68: syntax error before `&' token
    
93. In file included from /usr/local/pgsql/include/libpq++.h:33,
    
94.                  from cpptest.cc:2:
    
95. /usr/local/pgsql/include/libpq++/pgtransdb.h:38: syntax error before `:' token
    
96. /usr/local/pgsql/include/libpq++/pgtransdb.h:44: destructors must be member
    
97.    functions
    
98. /usr/local/pgsql/include/libpq++/pgtransdb.h:49: syntax error before `protected
    
99.    '
    
100. /usr/local/pgsql/include/libpq++/pgtransdb.h:59: syntax error before `&' token
     
101. /usr/local/pgsql/include/libpq++/pgtransdb.h:59: ISO C++ forbids declaration of
     
102.    `PgTransaction' with no type
     
103. /usr/local/pgsql/include/libpq++/pgtransdb.h:60: syntax error before `&' token
     
104. In file included from /usr/local/pgsql/include/libpq++.h:34,
     
105.                  from cpptest.cc:2:
     
106. /usr/local/pgsql/include/libpq++/pgcursordb.h:44: syntax error before `:' token
     
107. /usr/local/pgsql/include/libpq++/pgcursordb.h:50: destructors must be member
     
108.    functions
     
109. /usr/local/pgsql/include/libpq++/pgcursordb.h:53: `string' was not declared in
     
110.    this scope
     
111. /usr/local/pgsql/include/libpq++/pgcursordb.h:53: syntax error before `,' token
     
112. /usr/local/pgsql/include/libpq++/pgcursordb.h:56: new declaration `int Close()'
     
113. /usr/local/pgsql/include/libpq++/pglobject.h:53: ambiguates old declaration `
     
114.    void Close()'
     
115. /usr/local/pgsql/include/libpq++/pgcursordb.h:60: non-member function `const
     
116.    char* Cursor()' cannot have `const' method qualifier
     
117. /usr/local/pgsql/include/libpq++/pgcursordb.h: In function `const char*
     
118.    Cursor()':
     
119. /usr/local/pgsql/include/libpq++/pgcursordb.h:61: `pgCursor' undeclared (first
     
120.    use this function)
     
121. /usr/local/pgsql/include/libpq++/pgcursordb.h:61: (Each undeclared identifier
     
122.    is reported only once for each function it appears in.)
     
123. /usr/local/pgsql/include/libpq++/pgcursordb.h: At global scope:
     
124. /usr/local/pgsql/include/libpq++/pgcursordb.h:65: `string' was not declared in
     
125.    this scope
     
126. /usr/local/pgsql/include/libpq++/pgcursordb.h:65: syntax error before `)' token
     
127. /usr/local/pgsql/include/libpq++/pgcursordb.h: In function `void Cursor(...)':
     
128. /usr/local/pgsql/include/libpq++/pgcursordb.h:67: `cursor' undeclared (first
     
129.    use this function)
     
130. /usr/local/pgsql/include/libpq++/pgcursordb.h: At global scope:
     
131. /usr/local/pgsql/include/libpq++/pgcursordb.h:70: syntax error before `
     
132.    protected'
     
133. /usr/local/pgsql/include/libpq++/pgcursordb.h:85: syntax error before `&' token
     
134. cpptest.cc: In function `int main()':
     
135. cpptest.cc:8: `PgDatabase' undeclared (first use this function)
     
136. cpptest.cc:8: syntax error before `(' token
     
137. cpptest.cc:9: `data' undeclared (first use this function)

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请问这是为什么？ :confused:  :confused:  :confused:

下面是我的代码：

1. 
   
2. /** cpptest.cc*/
   
3. #include <iostream>
   
4. #include <libpq++.h>
   
5. 
   
6. using namespace std;
   
7. 
   
8. int  main() {
   
9.         char query_string[256]= "SELECT * FROM v;";
   
10.         PgDatabase data("dbname = test");
    
11.         if (data.ConnectionBad()) {
    
12.                 cout <<"connected failed" << endl;
    
13.                 cout <<"Error is "<<data.ErrorMessage() << endl;
    
14.         exit(1);
    
15.     }
    
16.     if (! data.ExecTuplesOk(query_string)) {
    
17.                 cout<<"Query Failed!" << endl;
    
18.                 exit(1);
    
19.     }
    
20.     for(int k=0; k<data.Fields(); k++) /**显示字段名称*/ {
    
21.         cout<<data.FieldName(k);
    
22.         cout <<"      "     ;
    
23.     }
    
24.     cout<<endl;
    
25.     for (int i = 0; i < data.Tuples(); i++) /**取得查询结果的记录数量*/  {
    
26.         for(int k=0; k<data.Fields(); k++) {
    
27.                 cout << data.GetValue(i,k);
    
28.                 cout <<" | "     ;
    
29.         }
    
30.         cout<<endl;
    
31.     }
    
32.     return 0 ;
    
33. }
    

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