Create version method

[NickNaso]

Create the version method that have the responsability to check the actual version of ghostscript. It's important to be sure that the correct version of the ghostsctipt library is loaded.

Base the code as in the reference manual:

typedef struct gsapi_revision_s {
    const char *product;
    const char *copyright;
    long revision;
    long revisiondate;
} gsapi_revision_t;
gsapi_revision_t r;

if (gsapi_revision(&r, sizeof(r)) == 0) {
    if (r.revision < 650)
       printf("Need at least Ghostscript 6.50");
}
else {
    printf("revision structure size is incorrect");
}

[NickNaso]

Please see the issue https://github.com/NickNaso/ghostscript4js/issues/3 to avoid the compilation error.

[NickNaso]

Example for C implementation

#include <stdlib.h>
#include <stdio.h>

#include <ghostscript/gdevdsp.h>
#include <ghostscript/gserrors.h>
#include <ghostscript/iapi.h>
#include <ghostscript/ierrors.h>

int main () { 

gsapi_revision_t r;

if (gsapi_revision(&r, sizeof(r)) == 0) {
    printf("%s", r.product);

    if (r.revision < 650)
       printf("Need at least Ghostscript 6.50");
}
else {
    printf("revision structure size is incorrect");
}
  return 0;
}

[NickNaso]

Example for C++ implementation

#include <iostream>
#include <string>

#include <ghostscript/gdevdsp.h>
#include <ghostscript/gserrors.h>
#include <ghostscript/iapi.h>
#include <ghostscript/ierrors.h>

using namespace std;

int main () { 

   gsapi_revision_t r;
   cout << sizeof(r);
   int res = gsapi_revision(&r, sizeof(r));

   cout << res;
   cout << r.product;

  return 0;
}

[NickNaso]

It will return an objet like this:

{
   product: "-------",
   copyright: "------",
   revision: "------",
   revisiondate: "------"
}

[NickNaso]

Method version implemented