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NAME

       libdmmp.h - Device Mapper Multipath API.

SYNOPSIS

       #include <libdmmp/libdmmp.h>

DESCRIPTION

       All  the libdmmp public functions ships its own man pages.  Use 'man 3 <function_name>' to
       check the detail usage.

USAGE

       To use libdmmp in your project, we suggest to use the 'pkg-config' way:

        * Add this line into your configure.ac:

           PKG_CHECK_MODULES([LIBDMMP], [libdmmp])

        * Add these lines into your Makefile.am:

           foo_LDFLAGS += $(LIBDMMP_LIBS)
           foo_CFLAGS += $(LIBDMMP_CFLAGS)

LOG HANDLING

       The log handler function could be set via 'dmmp_context_log_func_set()'.  The log priority
       could be set via 'dmmp_context_log_priority_set()'.

       By  default,  the  log  priorities  is  'DMMP_LOG_PRIORITY_WARNING'.   By default, the log
       handler is print log to STDERR, and its code is listed below in case you  want  to  create
       your own log handler.

               static int _DMMP_LOG_STRERR_ALIGN_WIDTH = 80;

               static void _log_stderr(struct dmmp_context *ctx,
                                       enum dmmp_log_priority priority,
                                       const char *file, int line,
                                       const char *func_name,
                                       const char *format, va_list args)
               {
                   int printed_bytes = 0;

                   printed_bytes += fprintf(stderr, "libdmmp %s: ",
                                            dmmp_log_priority_str(priority));
                   printed_bytes += vfprintf(stderr, format, args);
                   userdata = dmmp_context_userdata_get(ctx);
                   if (userdata != NULL)
                       fprintf(stderr, "(with user data at memory address %p)",
                               userdata);

                   if (printed_bytes < _DMMP_LOG_STRERR_ALIGN_WIDTH) {
                       fprintf(stderr, "%*s # %s:%s():%d0,
                               _DMMP_LOG_STRERR_ALIGN_WIDTH - printed_bytes, "", file,
                               func_name, line);
                   } else {
                       fprintf(stderr, " # %s:%s():%d0, file, func_name, line);
                   }
               }

SAMPLE CODE

           #include <libdmmp/libdmmp.h>

           int main(int argc, char *argv[]) {
               struct dmmp_context *ctx = NULL;
               struct dmmp_mpath **dmmp_mps = NULL;
               struct dmmp_path_group **dmmp_pgs = NULL;
               struct dmmp_path **dmmp_ps = NULL;
               uint32_t dmmp_mp_count = 0;
               uint32_t dmmp_pg_count = 0;
               uint32_t dmmp_p_count = 0;
               const char *name = NULL;
               const char *wwid = NULL;
               uint32_t i = 0;
               int rc = DMMP_OK;

               ctx = dmmp_context_new();
               dmmp_context_log_priority_set(ctx, DMMP_LOG_PRIORITY_DEBUG);
               // By default, log will be printed to STDERR, you could
               // change that via dmmp_context_log_func_set()
               rc = dmmp_mpath_array_get(ctx, &dmmp_mps, &dmmp_mp_count);
               if (rc != DMMP_OK) {
                   printf("dmmp_mpath_array_get() failed with %d: %s", rc,
                          dmmp_strerror(rc));
                   goto out;
               }
               for (i = 0; i < dmmp_mp_count; ++i) {
                       name = dmmp_mpath_name_get(dmmp_mps[i]);
                       wwid = dmmp_mpath_wwid_get(dmmp_mps[i]);
                       printf("dmmp_mpath_array_get(): Got mpath: %s %s0, name,
                              wwid);
                       // You could use dmmp_path_group_array_get() to retrieve
                       // path group information and then invoke dmmp_path_array_get()
                       // for path information.
               }

            out:
               dmmp_context_free(ctx);
               dmmp_mpath_array_free(dmmp_mps, dmmp_mp_count);
               if (rc != DMMP_OK)
                   exit(1);
               exit(0);
           }

LICENSE

       GPLv2+

BUG

       Please report bug to <dm-devel@redhat.com>

Device Mapper Multipath API - libdmmp ManuaJanuary 2016                              libdmmp.h(3)