7.7.3 How to check for software updates

The GnuPG Project operates a server to query the current versions of software packages related to GnuPG. GPGME can be used to access this online database and check whether a new version of a software package is available.

Data type: gpgme_query_swdb_result_t

SINCE: 1.8.0

This is a pointer to a structure used to store the result of a gpgme_op_query_swdb operation. After success full call to that function, you can retrieve the pointer to the result with gpgme_op_query_swdb_result. The structure contains the following member:

name

This is the name of the package.

iversion

The currently installed version or an empty string. This value is either a copy of the argument given to gpgme_op_query_swdb or the version of the installed software as figured out by GPGME or GnuPG.

created

This gives the date the file with the list of version numbers has originally be created by the GnuPG project.

retrieved

This gives the date the file was downloaded.

warning

If this flag is set either an error has occurred or some of the information in this structure are not properly set. For example if the version number of the installed software could not be figured out, the update flag may not reflect a required update status.

update

If this flag is set an update of the software is available.

urgent

If this flag is set an available update is important.

noinfo

If this flag is set, no valid information could be retrieved.

unknown

If this flag is set the given name is not known.

tooold

If this flag is set the available information is not fresh enough.

error

If this flag is set some other error has occurred.

version

The version string of the latest released version.

reldate

The release date of the latest released version.

Function: gpgme_error_t gpgme_op_query_swdb (gpgme_ctx_t ctx, const char *name, const char *iversion, gpgme_data_t reserved)

SINCE: 1.8.0

Query the software version database for software package name and check against the installed version given by iversion. If iversion is given as NULL a check is only done if GPGME can figure out the version by itself (for example when using "gpgme" or "gnupg"). If NULL is used for name the current gpgme version is checked. reserved must be set to 0.

Function: gpgme_query_swdb_result_t gpgme_op_query_swdb_result (gpgme_ctx_t ctx)

SINCE: 1.8.0

The function gpgme_op_query_swdb_result returns a gpgme_query_swdb_result_t pointer to a structure holding the result of a gpgme_op_query_swdb operation. The pointer is only valid if the last operation on the context was a successful call to gpgme_op_query_swdb. If that call failed, the result might be a NULL pointer. The returned pointer is only valid until the next operation is started on the context ctx.

Here is an example on how to check whether GnuPG is current:

#include <gpgme.h>

int
main (void)
{
  gpg_error_t err;
  gpgme_ctx_t ctx;
  gpgme_query_swdb_result_t result;

  gpgme_check_version (NULL);
  err = gpgme_new (&ctx);
  if (err)
    fprintf (stderr, "error creating context: %s\n", gpg_strerror (err));
  else
    {
      gpgme_set_protocol (ctx, GPGME_PROTOCOL_GPGCONF);

      err = gpgme_op_query_swdb (ctx, "gnupg", NULL, 0);
      if (err)
        fprintf (stderr, "error querying swdb: %s\n", gpg_strerror (err));
      else
        {
          result = gpgme_op_query_swdb_result (ctx);
          if (!result)
            fprintf (stderr, "error querying swdb\n");
          if (!result->warning && !result->update)
            printf ("GnuPG version %s is current\n",
                    result->iversion);
          else if (!result->warning && result->update)
            printf ("GnuPG version %s can be updated to %s\n",
                    result->iversion, result->version);
          else
            fprintf (stderr, "error finding the update status\n");
        }
      gpgme_release (ctx);
    }
  return 0;
}