I'm using IDA Pro and have identified a function that takes an std::string as an argument.

However when I click on the function and "Set Item Type", entering its definition:

std::__ndk1::basic_string<char,std::__ndk1::char_traits<char>,std::__ndk1::allocator<char>> funcname(const std::__ndk1::basic_string<char,std::__ndk1::char_traits<char>,std::__ndk1::allocator<char>>& foo)

I get a syntax error:

Syntax error near: std::__ndk1::basic_string

However there are other variables with this very type that IDA is able to use. Why is it failing when I try to set it?

  • 1
    From Ida Help: "The function type must be entered as a C declaration.". So it seems that you cannot use C++ classes while setting function type.
    – bart1e
    Commented Jun 20, 2020 at 17:47
  • Hmm seems tricky... so that leads to a very different question which is 'how do I deal with a C++ function taking C++ args..'
    – Claudiu
    Commented Jun 20, 2020 at 18:02
  • Anyway this seems the answer, I will upvote & accept if you post as answer
    – Claudiu
    Commented Jun 20, 2020 at 18:03

1 Answer 1


IDA’s C parser does not handle some C++ syntax like namespaces. There are two options:

  1. Rename the local type or struct to have no “wrong” symbols, you can use it in type declaration then
  2. Use “Convert to struct*” context menu command on the argument/variable. This bypasses the C parser and sets the type directly.

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