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astGetColumnData - Retrieve all the data values stored in a column

Description:
This function copies all data values from a named column into a supplied buffer
Synopsis:
void astGetColumnData( AstFitsTable $*$this, const char $*$column, float fnull, double dnull, size_t mxsize, void $*$coldata, int $*$nelem )
Parameters:
this
Pointer to the FitsTable.
column
The character string holding the name of the column. Trailing spaces are ignored.
fnull
The value to return in "coldata" for any cells for which no value has been stored in the FitsTable. Ignored if the column's data type is not AST__FLOATTYPE. Supplying AST__NANF will cause a single precision IEEE NaN value to be used.
dnull
The value to return in "coldata" for any cells for which no value has been stored in the FitsTable. Ignored if the column's data type is not AST__DOUBLETYPE. Supplying AST__NAN will cause a double precision IEEE NaN value to be used.
mxsize
The size of the "coldata" array, in bytes. The amount of memory needed to hold the data from a column may be determined using astColumnSize. If the supplied array is too small to hold all the column data, trailing column values will be omitted from the returned array, but no error will be reported.
coldata
A pointer to an area of memory in which to return the data values currently stored in the column. The values are stored in row order. If the column holds non-scalar values, the elements of each value are stored in "Fortran" order. No data type conversion is performed - the data type of each returned value is the data type associated with the column when the column was added to the table. If the column holds strings, the returned strings will be null terminated. Any excess room at the end of the array will be left unchanged.
nelem
The number of elements returned in the "coldata" array. This is the product of the number of rows returned and the number of elements in each column value.
Notes:
  • The "fnull" and "dnull" parameters specify the value to be returned for any empty cells within columns holding floating point values. For columns holding integer values, the value returned for empty cells is the value returned by the astColumNull function. For columns holding string values, the ASCII NULL character is returned for empty cells.


next up previous 264
Next: astGetFitsX - Get a named keyword value from a FitsChan
Up: AST Function Descriptions
Previous: astGetActiveUnit - Determines how the Unit attribute will be used

AST A Library for Handling World Coordinate Systems in Astronomy
Starlink User Note 211
R.F. Warren-Smith & D.S. Berry
7th December 2012
E-mail:starlink@jiscmail.ac.uk

Copyright (C) 2012 Science \& Technology Facilities Council