gd_nvectors(3) report the number of vector fields in a dirfile


#include <getdata.h>
unsigned int gd_nvectors(DIRFILE *dirfile);


The gd_nvectors() function queries a dirfile(5) database specified by dirfile and returns the number of vector fields defined in the database (i.e. fields of types BIT,~LINCOM,~LINTERP,~MULTIPLY,~PHASE,~POLYNOM,~RAW, SBIT). Notably, this count does not include /META fields.

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


Upon successful completion, gd_nvectors() returns the number of vector fields in the dirfile. On error, it returns zero and sets the dirfile error to a non-zero error value. Possible error values are:
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).