在gdb当中，display的功能很不错的
下面是gdb手册上的定义：
display expr Add the expression expr to the list of expressions to display each time your program stops. See Expressions.
display does not repeat if you press <RET> again after using it.
display/fmt expr For fmt specifying only a display format and not a size or count, add the expression expr to the auto-display list but arrange to display it each time in the specified format fmt. See Output Formats.
display/fmt addr For fmt `i' or `s', or including a unit-size or a number of units, add the expression addr as a memory address to be examined each time your program stops. Examining means in effect doing `x/fmt addr'. See Examining Memory.
这里讲一下显示数组：
假设定义了一个数组
char array[4];
那么在gdb当中就可以用如下的方式：
display /x *array@4
gdb就会吧array数组以十六进制显示了！～
