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Template function problem

Started by Wavarian Jun 26, 2004 at 3:57 AM 5 replies 1.1k views

Original Post

Wavarian

116

Wavarian

Jun 26, 2004 at 3:57 AM

Greets, I'm having a little trouble with templated functions which is better explained with the following example:


template <typename T>
void foo(){

	cout << sizeof(T) << "\n";
}

void main(){

	foo<char>();
	foo<int>();
}

The output is always 4 bytes. If I remove

foo<int>();

the output is 1 byte. Why is "T" taking on the larger of the two, even if it is supposed to be representing a single char value? Thanks very much in advance.

SiCrane

Mod

473

SiCrane

Jun 26, 2004 at 4:00 AM

I'm guessing broken compiler. Your code works fine under MSVC 7.1 and gcc 3.3.1.

DigitalDelusion

Jun 26, 2004 at 4:08 AM

Quote:
Original post by SiCrane
I'm guessing broken compiler. Your code works fine under MSVC 7.1 and gcc 3.3.1.

Im guessing VC6 here it's notoriously broken in the template department.

Wavarian

Author

116

Wavarian

Jun 26, 2004 at 4:11 AM

I didn't want to hear that =( but nevertheless, thanks alot guys =P I guess I'll just have to pass in the expected size as a parameter.

edit: and yes I'm using VC6 ><

risingdragon3

Jun 26, 2004 at 6:00 AM

Or you could specialize for most of the types. I assume you writing some input / output functions for binary mode file io?

void dostuff(int);
void dostuff(float);
void dostuff(char);
...
tedious, but blame vc6 :)

snk_kid

132

snk_kid

Jun 26, 2004 at 6:10 AM

Quote:
Original post by wAVaRiaN
I didn't want to hear that =( but nevertheless, thanks alot guys =P I guess I'll just have to pass in the expected size as a parameter.

edit: and yes I'm using VC6 ><

You could try updating your VC++6 with SP5 then SP6, or you can download VC++ .NET 2003 compiler for free but doesn't come with VS IDE.

Wavarian

Author

116

Wavarian

Jun 26, 2004 at 6:56 AM

I might try that a little later snk_kid, hopefully that fixes the problem.

And thanks for the input RD3, however it seems far more feasible to simply pass in the size of T for the time being rather than copy and paste a large block of code several times, and then have to go through and debug each should something need to be changed - hence the existance of templates =PP

It works fine now, but I will be sure to check out those patches, probably huge in size no doubt >=|

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