SLA_DBJIN - Decode String to B/J Epoch (DP)

ACTION:

Decode a character string into a DOUBLE PRECISION number, with special provision for Besselian and Julian epochs. The string syntax is as for sla_DFLTIN, prefixed by an optional `B' or `J'.

CALL:

CALL sla_DBJIN (STRING, NSTRT, DRESLT, J1, J2)

GIVEN:

STRING	C	string containing field to be decoded
NSTRT	I	pointer to first character of field in string

RETURNED:

NSTRT	I	incremented past the decoded field
DRESLT	D	result
J1	I	DFLTIN status:
		$-$1 = $-$OK
		0 = +OK
		1 = null field
		2 = error
J2	I	syntax flag:
		0 = normal DFLTIN syntax
		1 = `B' or `b'
		2 = `J' or `j'

NOTES:

1. The purpose of the syntax extensions is to help cope with mixed FK4 and FK5 data, allowing fields such as `B1950' or `J2000' to be decoded.
2. In addition to the syntax accepted by sla_DFLTIN, the following two extensions are recognized by sla_DBJIN:
   1. A valid non-null field preceded by the character `B' (or `b') is accepted.
   2. A valid non-null field preceded by the character `J' (or `j') is accepted.
3. The calling program is told of the `B' or `J' through an supplementary status argument. The rest of the arguments are as for sla_DFLTIN.