DEBUG模式下, 内存中的变量地址分析

测试函数的模板实现

1. /// @file my_template.h
2. /// @brief 测试数据类型用的模板实现
3. #ifndef MY_TEMPLATE_H_2016_0123_1226
4. #define MY_TEMPLATE_H_2016_0123_1226
5. template<int iArySize>
6. void fnTestDataType() {
7. char szBuf[iArySize] = {'\0'};
8. unsigned short wTmp = 0;
9. int iTmp = 0;
10. long lTmp = 0;
11. float f = .0f;
12. double dbl = .0;
13. char szBuf1[iArySize] = {'\0'};
14. unsigned short wTmp1 = 0;
15. int iTmp1 = 0;
16. long lTmp1 = 0;
17. float f1 = .0f;
18. double dbl1 = .0;
19. printf("============================================================\n");
20. printf("char array size = %d\n", iArySize);
21. printf("------------------------------------------------------------\n");
22. printf("&szBuf[0] = \t0x%p\n", &szBuf[0]);
23. printf("&szBuf[%d] = \t0x%p\n", iArySize - 1, &szBuf[iArySize - 1]);
24. printf("&wTmp = \t0x%p\n", &wTmp);
25. printf("&iTmp = \t0x%p\n", &iTmp);
26. printf("&lTmp = \t0x%p\n", &lTmp);
27. printf("&f = \t\t0x%p\n", &f);
28. printf("&dbl = \t\t0x%p\n", &dbl);
29. printf("&szBuf1[0] = \t0x%p\n", &szBuf1[0]);
30. printf("&szBuf1[%d] = \t0x%p\n", iArySize - 1, &szBuf1[iArySize - 1]);
31. printf("&wTmp1 = \t0x%p\n", &wTmp1);
32. printf("&iTmp1 = \t0x%p\n", &iTmp1);
33. printf("&lTmp1 = \t0x%p\n", &lTmp1);
34. printf("&f1 = \t\t0x%p\n", &f1);
35. printf("&dbl1 = \t0x%p\n\n", &dbl1);
36. };
37. #endif // #ifndef MY_TEMPLATE_H_2016_0123_1226

测试代码和实验结论

1. /// @file main.cpp
2. /// @brief DEBUG模式下, 内存中的变量地址分析
3. #include <iostream>
4. using namespace std;
5. #include "my_template.h"
6. /** 试验结论 - <<DEBUG模式下, 内存中的变量地址分析>>
7. 如果定义多个变量
8. DEBUG模式下, 内存中的变量地址和定义的顺序相同
9. 变量开始地址都是模式地址
10. 先定义的变量在内存高地址
11. 后定义的变量在内存低地址
12. Release模式下, 经过优化, 变量的内存地址和变量定义的顺序不相同!
13. 如果变量有越界访问的情况, Release模式下的越界访问情况未知.
14. 好像有一些规律, 依赖于编译器的优化选项
15. 依赖变量越界访问达成变量的存取, 在Release模式下会和Debug模式下的运行效果不相同.
16. 运行结果肯定不对了. 是否报错，要看运气了. 如果不报错, 发布后会死的很惨
17. */
18. int main(int argc, char* argv[]) {
19. /// 将函数模板特化的数组大小, 从1填到9来测试
20. /// 不能直接在一个作用域内写多个函数模板的实例, 会全被替换成最后一个函数模板的实例
21. fnTestDataType<9>();
22. printf(""); //< bp
23. /** IDE debug 变量内存地址分析
24. ============================================================
25. char array size = 9
26. ------------------------------------------------------------
27. &szBuf[0] =     0x0018FEE8
28. &szBuf[8] =     0x0018FEF0
29. &wTmp =         0x0018FEE4
30. &iTmp =         0x0018FEE0
31. &lTmp =         0x0018FEDC
32. &f =            0x0018FED8
33. &dbl =          0x0018FED0
34. &szBuf1[0] =    0x0018FEC4
35. &szBuf1[8] =    0x0018FECC
36. &wTmp1 =        0x0018FEC0
37. &iTmp1 =        0x0018FEBC
38. &lTmp1 =        0x0018FEB8
39. &f1 =           0x0018FEB4
40. &dbl1 =         0x0018FEAC
41. ============================================================
42. char array size = 8
43. ------------------------------------------------------------
44. &szBuf[0] =     0x0018FEEC
45. &szBuf[7] =     0x0018FEF3
46. &wTmp =         0x0018FEE8
47. &iTmp =         0x0018FEE4
48. &lTmp =         0x0018FEE0
49. &f =            0x0018FEDC
50. &dbl =          0x0018FED4
51. &szBuf1[0] =    0x0018FECC
52. &szBuf1[7] =    0x0018FED3
53. &wTmp1 =        0x0018FEC8
54. &iTmp1 =        0x0018FEC4
55. &lTmp1 =        0x0018FEC0
56. &f1 =           0x0018FEBC
57. &dbl1 =         0x0018FEB4
58. ============================================================
59. char array size = 7
60. ------------------------------------------------------------
61. &szBuf[0] =     0x0018FEEC
62. &szBuf[6] =     0x0018FEF2
63. &wTmp =         0x0018FEE8
64. &iTmp =         0x0018FEE4
65. &lTmp =         0x0018FEE0
66. &f =            0x0018FEDC
67. &dbl =          0x0018FED4
68. &szBuf1[0] =    0x0018FECC
69. &szBuf1[6] =    0x0018FED2
70. &wTmp1 =        0x0018FEC8
71. &iTmp1 =        0x0018FEC4
72. &lTmp1 =        0x0018FEC0
73. &f1 =           0x0018FEBC
74. &dbl1 =         0x0018FEB4
75. ============================================================
76. char array size = 6
77. ------------------------------------------------------------
78. &szBuf[0] =     0x0018FEEC
79. &szBuf[5] =     0x0018FEF1
80. &wTmp =         0x0018FEE8
81. &iTmp =         0x0018FEE4
82. &lTmp =         0x0018FEE0
83. &f =            0x0018FEDC
84. &dbl =          0x0018FED4
85. &szBuf1[0] =    0x0018FECC
86. &szBuf1[5] =    0x0018FED1
87. &wTmp1 =        0x0018FEC8
88. &iTmp1 =        0x0018FEC4
89. &lTmp1 =        0x0018FEC0
90. &f1 =           0x0018FEBC
91. &dbl1 =         0x0018FEB4
92. ============================================================
93. char array size = 5
94. ------------------------------------------------------------
95. &szBuf[0] =     0x0018FEEC
96. &szBuf[4] =     0x0018FEF0
97. &wTmp =         0x0018FEE8
98. &iTmp =         0x0018FEE4
99. &lTmp =         0x0018FEE0
100. &f =            0x0018FEDC
101. &dbl =          0x0018FED4
102. &szBuf1[0] =    0x0018FECC
103. &szBuf1[4] =    0x0018FED0
104. &wTmp1 =        0x0018FEC8
105. &iTmp1 =        0x0018FEC4
106. &lTmp1 =        0x0018FEC0
107. &f1 =           0x0018FEBC
108. &dbl1 =         0x0018FEB4
109. ============================================================
110. char array size = 4
111. ------------------------------------------------------------
112. &szBuf[0] =     0x0018FEF0
113. &szBuf[3] =     0x0018FEF3
114. &wTmp =         0x0018FEEC
115. &iTmp =         0x0018FEE8
116. &lTmp =         0x0018FEE4
117. &f =            0x0018FEE0
118. &dbl =          0x0018FED8
119. &szBuf1[0] =    0x0018FED4
120. &szBuf1[3] =    0x0018FED7
121. &wTmp1 =        0x0018FED0
122. &iTmp1 =        0x0018FECC
123. &lTmp1 =        0x0018FEC8
124. &f1 =           0x0018FEC4
125. &dbl1 =         0x0018FEBC
126. ============================================================
127. char array size = 3
128. ------------------------------------------------------------
129. &szBuf[0] =     0x0018FEF0
130. &szBuf[2] =     0x0018FEF2
131. &wTmp =         0x0018FEEC
132. &iTmp =         0x0018FEE8
133. &lTmp =         0x0018FEE4
134. &f =            0x0018FEE0
135. &dbl =          0x0018FED8
136. &szBuf1[0] =    0x0018FED4
137. &szBuf1[2] =    0x0018FED6
138. &wTmp1 =        0x0018FED0
139. &iTmp1 =        0x0018FECC
140. &lTmp1 =        0x0018FEC8
141. &f1 =           0x0018FEC4
142. &dbl1 =         0x0018FEBC
143. ============================================================
144. char array size = 2
145. ------------------------------------------------------------
146. &szBuf[0] =     0x0018FEF0
147. &szBuf[1] =     0x0018FEF1
148. &wTmp =         0x0018FEEC
149. &iTmp =         0x0018FEE8
150. &lTmp =         0x0018FEE4
151. &f =            0x0018FEE0
152. &dbl =          0x0018FED8
153. &szBuf1[0] =    0x0018FED4
154. &szBuf1[1] =    0x0018FED5
155. &wTmp1 =        0x0018FED0
156. &iTmp1 =        0x0018FECC
157. &lTmp1 =        0x0018FEC8
158. &f1 =           0x0018FEC4
159. &dbl1 =         0x0018FEBC
160. ============================================================
161. char array size = 1
162. ------------------------------------------------------------
163. &szBuf[0] =     0x0018FEF0
164. &szBuf[0] =     0x0018FEF0
165. &wTmp =         0x0018FEEC
166. &iTmp =         0x0018FEE8
167. &lTmp =         0x0018FEE4
168. &f =            0x0018FEE0
169. &dbl =          0x0018FED8
170. &szBuf1[0] =    0x0018FED4
171. &szBuf1[0] =    0x0018FED4
172. &wTmp1 =        0x0018FED0
173. &iTmp1 =        0x0018FECC
174. &lTmp1 =        0x0018FEC8
175. &f1 =           0x0018FEC4
176. &dbl1 =         0x0018FEBC
177. */
178. printf("END, press any key to quit\n");
179. return 0;
180. }

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