NAME¶

gd_mvector_list — retrieve a list of vector fields in a dirfile

SYNOPSIS¶

#include <getdata.h>

DESCRIPTION¶

The gd_mvector_list() function queries a dirfile(5) database specified by dirfile and returns a read-only list of names of the all vector type metafields for the specified parent field defined in the database (i.e. fields of types BIT, LINCOM, LINTERP, MULTIPLY, PHASE, POLYNOM, RAW, SBIT). 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. The array is terminated by a NULL pointer. The number of strings in the array can be obtained from a call to gd_nmvectors(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_mvector_list() is called again with the same arguments, or until the array is de-allocated by a call to gd_close(3).

RETURN VALUE¶

Upon successful completion, gd_mvector_list() returns a pointer to an array of strings containing the names of all the vector metafields for the given parent field. On error it returns NULL and sets the dirfile error to a non-zero error value. Possible error values are:

GD_E_ALLOC

The library was unable to allocate memory.

GD_E_BAD_CODE

The supplied parent field code was not found, or referred to a metafield itself.

GD_E_BAD_DIRFILE

The supplied dirfile was invalid.

The dirfile error may be retrieved by calling gd_error(3). A descriptive error string for the last error encountered can be obtained from a call to gd_error_string(3).

SEE ALSO¶

dirfile(5), gd_open(3), gd_error(3), gd_error_string(3), gd_mfield_list(3), gd_nmetavectors(3), gd_vector_list(3)