473,230 Members | 1,541 Online
Bytes | Software Development & Data Engineering Community
Post Job

Home Posts Topics Members FAQ

Join Bytes to post your question to a community of 473,230 software developers and data experts.

Simple question about templates

Hello,
I have a class with a number of functions like this one.

typedef unsigned char Pixel;
.....
template <class T>
void Image2D<T>::Char2Pixel(Pixel * c, T *p, int dimx, int dimy){
int i,j,k=0;

for(i=0;i<dimy;i++)
for(j=0;j<dimx;j++,k++){
p[k] = (T) c[k];
}
}

I can compile the class successfully. Now, I'm trying to generate a
shared library, but during the linking process I get the following
errors for all the my functions.

.....
libexample.so: undefined reference to `Image2D<unsigned
char>::Char2Pixel(unsigned char*, unsigned char*, int, int)'
libexample.so: undefined reference to
`Image2D<short>::Char2Pixel(unsigned char*, short*, int, int)'
libexample.so: undefined reference to
`Image2D<float>::Char2Pixel(unsigned char*, float*, int, int)'
.....

Any ideas what I'm doing wrong with my templates?

Thanks!

Jul 4 '06 #1
2 1179
In article <11*********************@h44g2000cwa.googlegroups. com>,
ne*******@yahoo.com says...
Hello,
I have a class with a number of functions like this one.
[ template code elided ... ]
I can compile the class successfully. Now, I'm trying to generate a
shared library, but during the linking process I get the following
errors for all the my functions.
Most compilers require that the source code to a template is visible
anywhere that template is used. A few support support export, so you
can put a template into a separate object file. I doubt any supports
putting one into a shared library though.

--
Later,
Jerry.

The universe is a figment of its own imagination.
Jul 4 '06 #2
neojohn75 wrote:
I have a class with a number of functions like this one.

typedef unsigned char Pixel;
....
template <class T>
void Image2D<T>::Char2Pixel(Pixel * c, T *p, int dimx, int dimy){
int i,j,k=0;

for(i=0;i<dimy;i++)
for(j=0;j<dimx;j++,k++){
p[k] = (T) c[k];
}
}

I can compile the class successfully. Now, I'm trying to generate a
shared library, but during the linking process I get the following
errors for all the my functions.

....
libexample.so: undefined reference to `Image2D<unsigned
char>::Char2Pixel(unsigned char*, unsigned char*, int, int)'
libexample.so: undefined reference to
`Image2D<short>::Char2Pixel(unsigned char*, short*, int, int)'
libexample.so: undefined reference to
`Image2D<float>::Char2Pixel(unsigned char*, float*, int, int)'
....

Any ideas what I'm doing wrong with my templates?
It's in the FAQ:

http://www.parashift.com/c++-faq-lit...html#faq-35.13

Best regards,

Tom

Jul 4 '06 #3

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

3
by: Chris Stiles | last post by:
Hi -- Does anyone have any recommendations for simple web templating systems for python that also allow execution of python code within the the templates themselves ? So far I'm using...
6
by: chris | last post by:
Hi, After going back through the XSL tutorials and the help here I have largely solved the problem of merging two XHTML files, but one small detail remains... The parser outputs <html...
9
by: Mike King | last post by:
What is the XPath expression that selects the value attribute in the following xml? <?xml version="1.0"?> <root xmlns="http://a/" xmlns:a="http://a/"> <child a:value="1"/> </root>
1
by: Scott | last post by:
The following is the XML I have to work with. Below is the question <Table0> <CaseID>102114</CaseID> <CaseNumber>1</CaseNumber> <DateOpened>2005-06-14T07:26:00.0000000-05:00</DateOpened>...
4
by: ³\¥\»\ | last post by:
I have reviewed all famous and mature CMS but there are ALL too complicated, too fancy and the result is that you can not totally control what you want in your website. I hope there is a CMS with:...
5
by: Support | last post by:
Hello: I have the following code that currently needs to go in every page. QUESTION 1) Can Page_Preinit go somewhere else more global like Global.asax so that I dont have to copy this code in...
75
by: Steven T. Hatton | last post by:
No, this is not a troll, and I am not promoting Java, C-flat, D, APL, Bash, Mathematica, SML, or LISP. A college teacher recently posted to this newsgroup regarding her observation that there has...
17
by: JohnQ | last post by:
Is that I can approximate using my ideal of a language in it. On the flip side, what I dislike most about it is all the flak/protecting-the-golden-calf one gets when using it that way. I think a...
3
by: stdlib99 | last post by:
Hi, I have a simple question regarding templates and meta programming. I am going to try and work my way through the C++ Template Metaprogramming, a book by David Abrahams and Aleksey...
0
by: VivesProcSPL | last post by:
Obviously, one of the original purposes of SQL is to make data query processing easy. The language uses many English-like terms and syntax in an effort to make it easy to learn, particularly for...
3
isladogs
by: isladogs | last post by:
The next Access Europe meeting will be on Wednesday 3 Jan 2024 starting at 18:00 UK time (6PM UTC) and finishing at about 19:15 (7.15PM). For other local times, please check World Time Buddy In...
0
by: jianzs | last post by:
Introduction Cloud-native applications are conventionally identified as those designed and nurtured on cloud infrastructure. Such applications, rooted in cloud technologies, skillfully benefit from...
0
by: stefan129 | last post by:
Hey forum members, I'm exploring options for SSL certificates for multiple domains. Has anyone had experience with multi-domain SSL certificates? Any recommendations on reliable providers or specific...
0
Git
by: egorbl4 | last post by:
Скачал я git, хотел начать настройку, а там вылезло вот это Что это? Что мне с этим делать? ...
0
by: MeoLessi9 | last post by:
I have VirtualBox installed on Windows 11 and now I would like to install Kali on a virtual machine. However, on the official website, I see two options: "Installer images" and "Virtual machines"....
0
by: DolphinDB | last post by:
The formulas of 101 quantitative trading alphas used by WorldQuant were presented in the paper 101 Formulaic Alphas. However, some formulas are complex, leading to challenges in calculation. Take...
0
by: DolphinDB | last post by:
Tired of spending countless mintues downsampling your data? Look no further! In this article, you’ll learn how to efficiently downsample 6.48 billion high-frequency records to 61 million...
0
by: Aftab Ahmad | last post by:
Hello Experts! I have written a code in MS Access for a cmd called "WhatsApp Message" to open WhatsApp using that very code but the problem is that it gives a popup message everytime I clicked on...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.