NAME

       gensio_add_default,    gensio_set_default,   gensio_get_default,   gensio_get_defaultaddr,
       gensio_del_default, gensio_reset_defaults - Handle default values for gensios

SYNOPSIS

       #include <gensio/gensio.h>
       struct gensio_enum_val {
           char *name;
           int val;
       };

       int gensio_add_default(struct gensio_os_funcs *o,
                           const char *name,
                           enum gensio_default_type type,
                           const char *strval, int intval,
                           int minval, int maxval,
                           const struct gensio_enum_val *enums);

       int gensio_set_default(struct gensio_os_funcs *o,
                           const char *class, const char *name,
                           const char *strval, int intval);

       int gensio_get_default(struct gensio_os_funcs *o,
                           const char *class, const char *name,
                           bool classonly,
                           enum gensio_default_type type,
                           char **strval, int *intval);

       int gensio_get_defaultaddr(struct gensio_os_funcs *o,
                           const char *class, const char *name,
                           bool classonly,
                           int iprotocol, bool listen,
                           bool require_port,
                           struct addrinfo **rai);

       int gensio_del_default(struct gensio_os_funcs *o,
                           const char *class, const char *name,
                           bool delclasses);

       int gensio_reset_defaults(struct gensio_os_funcs *o);

DESCRIPTION

       Defaults provide a way to set overall or class-based defaults for gensio options  (or  you
       can  use  it  yourself  to create your own defaults).  The various options for gensios are
       described in gensio(5).

       For default values, each class will use gensio_get_default with  their  class  (serialdev,
       telnet,  ssl,  etc.)  with the name as the given option name.  If a value has been set for
       its class, it will use that value.  If a value has been set with  class  set  to  NULL  (a
       "global"  default)  then  the  value will be used from there.  Otherwise the code will use
       it's own internal default value.

       Any option provided in the gensio string will override any default value, of course.

       The classonly parameter means to not look in the global defaults.  If  you  use  this  for
       your  own  defaults,  it  is  recommended that you use your own class and set classonly to
       true.

       Defaults  come  in  one   of   four   formats   defined   by   type:   GENSIO_DEFAULT_INT,
       GENSIO_DEFAULT_BOOL,  GENSIO_DEFAULT_ENUM,  GENSIO_DEFAULT_STR,  GENSIO_DEFAULT_DATA.  int
       and bool are pretty self-explanatory.  Except that if you pass in a non-NULL  strval  when
       setting  one,  the code will attempt to get the value from the strval and will return NULL
       if the value is not valid.  It will attempt to  translate  "true"  and  "false"  for  bool
       values.   If  the  value  is  <minval  or  >maxval, GE_OUTOFRANGE is returned from any set
       operation.

       When setting a str, the value is copied, you don't  have  to  keep  the  copy  around  for
       yourself.

       When  getting  a string value, the value is duplicated with gensio_strdup, you should free
       it with o->free().

       Data is like strings, except the length is passed in intval and it is  returned  the  same
       way.   This  will  hold  arbitrary  raw data.  Like strings, when you get a data value you
       should free it with o->free().

       If it's a enum, setting the value you will pass in a string and a table of possible values
       in  enum  (terminated  with a NULL name).  The code will look up the string you pass in in
       the enums table, and set the value to the integer value.  If the  string  is  not  in  the
       enums table, it will return GE_INVAL.  When you get the value, it will return the value in
       intval.

       When getting the value, the type must match what is set in the set call.  If the  name  is
       not  found,  GE_NOTFOUND  is  returned.   If  the  type  does  not match, then GE_INVAL is
       returned.  Note that if you save a value as an enum, you can fetch it as an int.

       Setting the same default again will replace the old value.

       gensio_del_default deletes the given default.  You can only  delete  user-added  defaults,
       not  ones  created  by  the  gensio  library.   If  there  are  any class-specific default
       registered against the default, this call will fail with  GE_INUSE  unless  delclasses  is
       true, which will cause all the class defaults to be deleted, too.

       gensio_reset_defaults will reset all defaults to the value set when gensio_add_default was
       called to create the default, or the built-in default value.

       gesnio_get_defaultaddr  gets  an   address   from   the   given   default   string.    See
       gensi_scan_network_port  in  gensio/gensio.h  for  details on how the string is formatted,
       what the parameters mean, and how to handle the addrinfo struct.

RETURN VALUES

       Zero is returned on success, or a gensio error on failure.

SEE ALSO

       gensio_err(3), gensio(5)

                                           27 Feb 2019                      gensio_add_default(3)