Template argument 1 is invalid error in C++

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Error which I am getting

'template argument 1 is invalid'
   std::function<AbstractStrategyHelper*(AbstractStrategy*)> strategyHelperAccessor;
'std::function’ is not a type
   void setStrategyHelperAccessor(std::function<AbstractStrategyHelper*(AbstractStrategy*)> f);

In this line of code

void setStrategyHelperAccessor(std::function<AbstractStrategyHelper*(AbstractStrategy*)> f);

What I have tried:

Why am I getting this error and how to fix it?

Posted 22-Dec-20 4:16am

User 14731409

Updated 22-Dec-20 13:47pm

v2

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Richard MacCutchan 22-Dec-20 10:25am

Where are AbstractStrategyHelper and AbstractStrategy declarde, and what are they.

[no name] 22-Dec-20 10:33am

They are abstract classes.

[no name] 22-Dec-20 10:38am

I have include the above classes and functional headerfile as well

Richard MacCutchan 22-Dec-20 10:43am

I just compiled that using Windows C++ compiler and it works. There must be something else in your code that is causing the problem.

[no name] 23-Dec-20 0:37am

@Richard MacCutchan thanks, am trying to find where I am doing mistake.

Richard MacCutchan 23-Dec-20 6:00am

There is other information which you are not showing here.

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Shao Voon Wong · Answer 1 · 2020-12-22T13:47:00

Solution 1

Include this header for std::function.

C++

#include <functional>

Posted 22-Dec-20 13:47pm

Shao Voon Wong

Comments

[no name] 22-Dec-20 20:10pm

I have included this header file

Shao Voon Wong 22-Dec-20 22:55pm

Then your error in your post is misleading. Please include the actual error messages.

Shao Voon Wong 22-Dec-20 23:05pm

Your code looks fine. The problem could be the compiler cannot find the class declaration/definition you supplied to std::function.

[no name] 23-Dec-20 0:38am

@Shao Voon Wong thanks for helping {:)I am trying to find what mistake I am doing.