Solved

Building dll in Microsoft C++

Posted on 1999-01-28
8
238 Views
Last Modified: 2010-04-16
HI,

I have been trying to build DLL in MS C++ using extern "C".
Here is my simple code:

#include <stdio.h>^M
#include <math.h>^M
^M
/* extern "C" */^M
extern "C" _declspec(dllexport) void calc1(float,float);^M
^M
void calc1(float x,float y)^M
/* test subroutine for building library */^M
{^M
float z;^M
^M
z= x + y;^M
printf("x=%.2f y=%.2f z=%.2f\n",x,y,z);^M
^M
/* end calc1 */^M
}^M

I just want to compile this in command line mode.
To compile from command line, we used^M
^M
cl -c calc1.c^M
^M
We get the following error message:^M
^M
calc1.c(5) : error C2059: syntax error : 'string'^M

Why is this happening? What am I doing wrong?

Thank you!

JJ


0
Comment
Question by:jinjool
8 Comments
 
LVL 1

Expert Comment

by:peter_vc
ID: 1185448
JJ,

I thought you only had to use the extern "C" directive in cpp files.  I believe the compiler is smart enough to know that you are compiling a file with a .C extension, and therefore you should not require the "C".

Peter


0
 
LVL 22

Expert Comment

by:nietod
ID: 1185449
peter_vc, I think you found the problem, but you expained it backwards.  The problem is that with a ".c" extension it compiles the program as a C program not a C++ program.  But the solution is to change the file to have a ".cpp" extension.  That way it is compiled as a C++ program.  (I assume that jinjool intended for it to be a C++ program, or he wouldn't have C++ syntax.)
0
 
LVL 4

Expert Comment

by:pellep
ID: 1185450
Compiler error C2059 is usually a Syntax Error. line 5 is the printf() command. maybe it's not the extern "C" that's the problem...
0
 
LVL 22

Expert Comment

by:nietod
ID: 1185451
That line seems fine and is nowhere near 5.
0
Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

 
LVL 23

Expert Comment

by:chensu
ID: 1185452
Are you using Microsoft C/C++ 7.0 or Microsoft Visual C++? Which version?

Line 5 is extern "C" _declspec(dllexport) void calc1(float,float);
0
 

Author Comment

by:jinjool
ID: 1185453
Thank you all for your comments.
Yes, nietod was right. The problem was-- the person who
did the program was running it without a .cpp extension.
I should have known it but somehow completely overlooked
the error.

Thanks again,
JJ
0
 
LVL 23

Expert Comment

by:chensu
ID: 1185454
So, the points should be given to nietod.
0
 
LVL 22

Accepted Solution

by:
nietod earned 50 total points
ID: 1185455
Answering as suggested by Chensu (Thanks).  (Sorry, for the delay, I was out of town.)
0

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
Lambda for random numbers problem 7 107
AVI wait icons for CAnimateCtrl in Visual Studio 2008 MFC 1 121
computer science syllabus 3 70
Why isn't object file created? 6 42
In days of old, returning something by value from a function in C++ was necessarily avoided because it would, invariably, involve one or even two copies of the object being created and potentially costly calls to a copy-constructor and destructor. A…
Container Orchestration platforms empower organizations to scale their apps at an exceptional rate. This is the reason numerous innovation-driven companies are moving apps to an appropriated datacenter wide platform that empowers them to scale at a …
The goal of the video will be to teach the user the difference and consequence of passing data by value vs passing data by reference in C++. An example of passing data by value as well as an example of passing data by reference will be be given. Bot…
The viewer will be introduced to the member functions push_back and pop_back of the vector class. The video will teach the difference between the two as well as how to use each one along with its functionality.

867 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

17 Experts available now in Live!

Get 1:1 Help Now