Scilab Function
Last update : 07/03/2006

link - incremental linker

### Calling Sequence

  `x=link(files [, sub-names,flag]);`
  `link(x , sub-names [, flag]);`
  `ulink(x)`
  `lst=link('show')`

### Parameters

- `files`: a character string or a vector of character strings, the files names used to define the new entry point (compiled routines, user libraries, system libraries,..)
- `sub-names`: a character string or a vector of character strings . Name of the entry points in `files` to be linked.
- `x`: an integer which gives the id of a shared library linked into Scilab with a previous call to `link`.
- `flag`: character string `'f'` or `'c'` for Fortran (default) or C code.

### Description

`link` is a incremental link facility based on the dld library: this command allows to add new compiled Fortran or C routines to Scilab executable code. Linked routines can be called interactively by the function `fort`. Linked routines can also be used as "external" for e.g. non linear problem solvers (`ode`, `optim`, `intg`, `dassl`...).

a call to `link` returns an integer which gives the id of the shared library which is loaded into Scilab. This number can then be used as the first argument of the link function in order to link additional function from the linked shared library. The shared library is removed with the `ulink` command.

A routine can be unlinked with `ulink`. If the linked function has been modified between two links, it is required to `ulink` the previous instance before the new link.

`link('show')` returns the current linked routines.

To be able to link routines in a system independent way, it is convenient to use the `ilib_for_link` utility function instead of `link`.

(Experienced) users may also `link` a new Scilab interface routine to add a set of new functions. See `intersci` documentation for interface generation and `ilib_build` and `addinter` functions.

### Examples

        //Example of the use of ilib_for_link with  a simple C code
        f1=['#include <math.h>'
        'void fooc(c,a,b,m,n)'
        'double a[],*b,c[];'
        'int *m,*n;'
        '{'
        '   int i;'
        '   for ( i =0 ; i < (*m)*(*n) ; i++) '
        '     c[i] = sin(a[i]) + *b; '
        '}'];

        mputl(f1,'fooc.c')

        //creating the shared library: a Makefile and a loader are
        //generated, the code is compiled and a shared library built.
        ilib_for_link('fooc','fooc.o',[],"c")

        // display the loader.sce file which calls link
        mprintf('%s\n',mgetl('loader.sce'))
        // load the shared library
        exec loader.sce

        link('show')
        // call the new linked entry point
        a=linspace(0,%pi,10);b=5;
        y1=call('fooc',a,2,'d',b,3,'d',size(a,1),4,'i',size(a,2),5,'i','out',size(a),1,'d')
        // check
        y1-(sin(a)+b)

### See Also

`call`, `external`, `c_link`, `addinter`, `ilib_for_link`, `ilib_build`,