Couldnot execute the dynamically linked program - c

Question

Hi I tried doing static library and a shared library with the gnu compiler, here is following code
following is the code for the library
calc_mean.c
double mean(double a, double b){
return (a+b)/2;
}
following is my header file calc_mean.h
double mean(double,double);
Now i started creating static library using following commands
first , calc_mean.c is turned into an object file
gcc -c calc_mean.c -o calc_mean.o
second ,the archiver (ar) is invoked to produce a static
library (named libmean.a) out of the object file calc_mean.o
ar rcs libmean.a calc_mean.o
third, created shared library before that using -fPIC option
created an independant code which is necessary for shared library
gcc -c -fPIC calc_mean.c -o calc_mean.o
now the shared library is created using following command line
gcc -shared -Wl,-soname,libmean.so.1 -o libmean.so.1.0.1 calc_mean.o
finally my main.c file that uses the library is as follows
#include <stdio.h>
#include "calc_mean.h"
int main(int argc, char* argv[]){
double v1,v2,m;
v1 = 5.2;
v2 = 7.9;
m=mean(v1,v2);
printf("The mean of %3.2f and %3.2f is %3.2f\n",v1,v2,m);
return 0;
}
finally I linked the program against static library that generated a statically_linked.exe
gcc -static main.c -L. -lmean -o statically_linked
when dynamically linked, it generated a dynamically_linked.exe with the following command
gcc main.c -o dynamically_linked -L. -lmean
Now when i use the command to execute the dynamically linked program using the following command, Iam getting an error message saying LD_LIBRARY is not recognized as an internal or external command,operable program or batch file
LD_LIBRARY_PATH=.D:\c\project3./dynamically_linked
how can I execute the dynamically linked program?

Answer 1

Your last line suggests that you do all this on windows. But you seem to have followed a step by step guide for linux or another *nix platform.
On windows, a dynamically linked library is in .dll format (not .so) and there's no versioning convention, so the command to create the shared library should look a little different.
Instead of:
gcc -shared -Wl,-soname,libmean.so.1 -o libmean.so.1.0.1 calc_mean.o
do the following on windows:
gcc -shared -Wl,--out-implib,libmean.dll.a -o mean-1.dll calc_mean.o
This creates the library itself named mean-1.dll as well as an import library named libmean.dll.a. The import library (sometimes called .lib instead of .dll.a) on the windows platform is just a stub used during linking of your program, AFAIK MinGW doesn't need it, but other compilers could.
Linking your main program should then work with the same command:
gcc main.c -o dynamically_linked -L. -lmean
And for finding .dll libraries in windows, there is no LD_LIBRARY_PATH -- windows just looks for them in the standard search path, including the directory of the .exe requiring it. IOW, you should be able to just run your program.