gd_sarrays, gd_msarrays — retrieve a list of SARRAY values from a Dirfile
const char ***gd_sarrays(DIRFILE *dirfile);
const char ***gd_msarrays(DIRFILE *dirfile, const char *parent);
The gd_sarrays() function queries a dirfile(5) database specified by dirfile and generates a read-only list of values of the all top-level SARRAY fields defined in the database, after type conversion to the data type specified by return_type. For a list of valid symbols to use for return_type, see the gd_get_sarray(3) manual page.
The gd_msarrays() function behaves similarly, but creates a list of values of SARRAY subfields under the parent field parent.
The dirfile argument must point to a valid DIRFILE object previously created by a call to gd_open(3).
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, except that it is guaranteed to be in the same order as the list of SARRAY fields returned by gd_field_list_by_type(3) or gd_mfield_list_by_type(3). The number of values in the array can be obtained from a call to gd_nfields_by_type(3) or gd_nmfields_by_type(3).
The caller may not modify any values in the array, nor the array itself. Doing so may cause database corruption. The pointer returned is guaranteed to be valid only until the function is called again with the same arguments, or until the dirfile's metadata is modified (by adding, modifying or deleting an entry), or until the array is de-allocated by a call to gd_close(3) or gd_discard(3).
Upon successful completion, gd_sarrays() and gd_msarrays(3) return a pointer to an array of arrays of strings. For convenience, both levels of the array are terminated by NULL pointers.
If no SARRAYs are defined in the database, a pointer to a single-element array containing only the terminating NULL is returned.
On error, gd_sarrays() returns NULL and stores 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:
- The library was unable to allocate memory.
- The supplied dirfile was invalid.
- An internal error occurred in the library while trying to perform the task. This indicates a bug in the library. Please report the incident to the GetData developers.
A descriptive error string for the error may be obtained by calling gd_error_string(3).
The gd_sarrays() function appeared in GetData-0.10.0.
|25 December 2016||Version 0.10.0|