error C2059: syntax error : ''

Question

This is My Visual C++ Code Used for Hardware Driver But i am getting follwoing error at Compile time.

template<class _A, class _R>
struct unary_function {
typedef _A argument_type;
typedef _R result_type;
};

Show the code, which is causing error. See the long error in output. This code you have shown is not the actual reason, how you've used is the actual source of error. — Ajay, Jul 16 '15 at 10:15
Post an [MCVE](http://stackoverflow.com/help/mcve), please. Something we could copy&paste into a file, compile it, and see the error ourselves. — Angew is no longer proud of SO, Jul 16 '15 at 10:25
@SatyavanChoure: _Why_ are you using Visual Studio 6.0? That IDE and compiler _predate standard C++ itself_. They are almost TWENTY years old. They have many infamous oddities to the extent that I would be content writing off this entire question as moot and instructing you to use a compiler from _this_ millennium and century. — Lightness Races in Orbit, Jul 16 '15 at 10:59

score 4 · Answer 1 · edited May 23 '17 at 12:21

4

Don't use identifiers beginning with an underscore and a capital, they are reserved by the implementation. Most probably _A or _R is already defined to something that does not make any sense when substituted into your code.

See : What are the rules about using an underscore in a C++ identifier?

edited May 23 '17 at 12:21

Community

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answered Jul 16 '15 at 10:12

Quentin

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And `unary_function` has been used for `std::unary_function`. – songyuanyao Jul 16 '15 at 10:15
@songyuanyao as long as there's no [`using namespace std;`](http://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice) that shouldn't technically be an issue. – Quentin Jul 16 '15 at 10:16
2

@Ajay can you prove it ? The snippet is perfectly valid apart from these identifiers. – Quentin Jul 16 '15 at 10:19
I have tried this but not working in my case..Still same problem ...Same compile time error... – Satyavan Choure Jul 16 '15 at 10:41
@SatyavanChoure no clash with `std::unary_function` either, as songyuanyao pointed out ? – Quentin Jul 16 '15 at 10:43
1

Probably just a bug. VS6 predates standard C++ and has many oddities. This entire question is frankly moot. – Lightness Races in Orbit Jul 16 '15 at 11:00
@LightnessRacesinOrbit wow ! I knew VS6 was old, but not *that* old... Do we have a "ancient artifact crumbled upon inspection" vote-to-close reason ? – Quentin Jul 16 '15 at 11:05
@Quentin: "Problem that can no longer be reproduced"? ;) – Lightness Races in Orbit Jul 16 '15 at 11:08

error C2059: syntax error : ''

1 Answers1