NAME

       gd_strings — retrieve a list of string values from a Dirfile

SYNOPSIS

       #include <getdata.h>

       const char **gd_strings(DIRFILE *dirfile);

       const char **gd_mstrings(DIRFILE *dirfile, const char *parent);

DESCRIPTION

       The  gd_strings()  function  queries  a dirfile(5) database specified by dirfile and compiles a read-only
       list of values of the all STRING type fields defined in the database, excluding /META subfields.

       The gd_mstrings() function produces the same list, but for STRING meta subfields of the indicated  parent
       field.

       The dirfile argument must point to a valid DIRFILE object previously created by a call to gd_open(3).

RETURN VALUE

       Upon  successful  completion, gd_strings() returns a pointer to an array of strings containing the values
       of all the STRING fields defined in the dirfile database.  Similarly, gd_mstrings() returns a pointer  to
       an array of strings containing the values of all the STRING metafields under parent.

       The  returned array is terminated by a NULL pointer.  A valid pointer is always returned if this function
       does not encounter an error.  If there are no string values to return, a pointer to an  array  consisting
       of only the NULL pointer is returned.

       The  array  returned  will be de-allocated by a call to gd_close(3) and should not be de-allocated by the
       caller.  The list returned should not be assumed to be in any particular order, although it is guaranteed
       to be in the same order as the list of STRING fields returned by gd_field_list_by_type(3).  The array  is
       terminated  by  a  NULL  pointer.   The  number  of  strings  in the array can be obtained from a call to
       gd_nfields_by_type(3).

       The caller may not modify any strings in the array, or the array itself.  Doing  so  may  cause  database
       corruption.  The pointer returned is guaranteed to be valid until gd_strings() or gd_mstrings() is called
       again  with  the  same  arguments,  or  until  the  array  is  de-allocated  by  a call to gd_close(3) or
       gd_discard(3).

       On error, these functions return NULL and store a negative-valued error code in the DIRFILE object  which
       may be retrieved by a subsequent call to gd_error(3).  Possible error codes are:

       GD_E_ALLOC
               The library was unable to allocate memory.

       GD_E_BAD_CODE
               (gd_mstrings() only) The supplied parent field code was not found, or referred to a metafield it‐
               self.

       GD_E_BAD_DIRFILE
               The supplied dirfile was invalid.

       A descriptive error string for the error may be obtained by calling gd_error_string(3).

HISTORY

       The get_strings() function appeared in GetData-0.3.0.

       The get_mstrings() function appeared in GetData-0.4.0.

       In GetData-0.7.0, these functions were renamed to gd_strings() and gd_mstrings().

SEE ALSO

       gd_error(3),   gd_error_string(3),   gd_field_list_by_type(3),   gd_mstrings(3),   gd_nfields_by_type(3),
       gd_open(3), gd_string(3), dirfile(5)

Version 0.10.0                                  25 December 2016                                   gd_strings(3)