GDB如何从内置python更改便利变量

Question

如何从gdb的内置python向gdb便利变量赋值？我认为它应该很简单，因为它是在尝试实现用户定义函数时自然产生的。但是我什么也没找到。在

UPD:添加了一个简化示例。但我的实际功能更复杂。不管怎样，将一个变量从python转移到gdb的方法会有很大帮助。在

用法示例（achtung！-它会引发一个错误）：

#accept a string, return it's lenght
define RetLenOfArg
  py arg0 = gdb.parse_and_eval("$arg0")
  set $Retrn = py len(arg0)
end

Answer 1

exist gdb的python API来获取/设置便利变量：来自documentation

Function: gdb.convenience_variable (name) Return the value of the convenience variable (see Convenience Vars) named name. name must be a string. The name should not include the ‘$’ that is used to mark a convenience variable in an expression. If the convenience variable does not exist, then None is returned.

Function: gdb.set_convenience_variable (name, value) Set the value of the convenience variable (see Convenience Vars) named name. name must be a string. The name should not include the ‘$’ that is used to mark a convenience variable in an expression. If value is None, then the convenience variable is removed. Otherwise, if value is not a gdb.Value (see Values From Inferior), it is is converted using the gdb.Value constructor.

Answer 2

accept a string, return it's lenght

如果确实需要strlen，可以使用$_strlen-一个内置的gdb便利函数，用于计算字符串长度：

(gdb) set $Retrn=$_strlen("test")
(gdb) p $Retrn
$4 = 4

how to assign something to a GDB convenience variable from a built-in python?

你可以用gdb.执行公司名称：

^{pr2}$

这是一个测试：

>gdb -q -x my_own_len.py
(gdb) p $_strlen("test")
$1 = 4
(gdb) p $my_own_len("test")
$2 = 4
(gdb) p $Retrn
$3 = 4
(gdb)