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astFormat - Format a coordinate value for a Frame axis

Description:
This function returns a pointer to a string containing the formatted (character) version of a coordinate value for a Frame axis. The formatting applied is determined by the Frame's attributes and, in particular, by any Format attribute string that has been set for the axis. A suitable default format (based on the Digits attribute value) will be applied if necessary.

Synopsis:
const char *astFormat( AstFrame *this, int axis, double value )

Parameters:
this
Pointer to the Frame.
axis
The number of the Frame axis for which formatting is to be performed (axis numbering starts at 1 for the first axis).
value
The coordinate value to be formatted.

Returned Value:
astFormat()
A pointer to a null-terminated string containing the formatted value.

Notes:
  • The returned pointer is guaranteed to remain valid and the string to which it points will not be over-written for a total of 50 successive invocations of this function. After this, the memory containing the string may be re-used, so a copy of the string should be made if it is needed for longer than this.
  • A formatted value may be converted back into a numerical (double) value using astUnformat.
  • A NULL pointer will be returned if this function is invoked with the AST error status set, or if it should fail for any reason.



next up previous
Next: astFrame - Create a Frame
Up: AST Function Descriptions
Previous: astFitsChan - Create a FitsChan

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
30th April 2003
E-mail:ussc@star.rl.ac.uk

Copyright (C) 2003 Central Laboratory of the Research Councils