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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:
(a)
A valid non-null field preceded by the character `B' (or `b') is accepted.
(b)
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.


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Next: SLA_DC62S - Cartesian 6-Vector to Spherical
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SLALIB --- Positional Astronomy Library
Starlink User Note 67
P. T. Wallace
12 October 1999
E-mail:ptw@star.rl.ac.uk