Defined Symbolic Constants

A number of symbolic constants have been defined within CFITSIO (in fitsio.h) for the convenience of application programmers. Use of these symbolic constants, rather than the actual numeric value, may help to make the source code more readable and easier for others to understand.

String Lengths, for use when allocating character arrays:

  #define FLEN_KEYWORD    9  /* max length of a keyword                   */
  #define FLEN_CARD      81  /* max length of a FITS header card          */
  #define FLEN_VALUE     71  /* max length of a keyword value string      */
  #define FLEN_COMMENT   73  /* max length of a keyword comment string    */
  #define FLEN_ERRMSG    81  /* max length of a FITSIO error message      */
  #define FLEN_STATUS    31  /* max length of a FITSIO status text string */

Access modes when opening a FITS file:

  #define READONLY  0
  #define READWRITE 1

BITPIX code values for FITS image data types:

  #define BYTE_IMG      8  /*  8-bit unsigned integers */
  #define SHORT_IMG    16  /* 16-bit   signed integers */
  #define LONG_IMG     32  /* 32-bit   signed integers */
  #define FLOAT_IMG   -32  /* 32-bit single precision floating point */
  #define DOUBLE_IMG  -64  /* 64-bit double precision floating point */

  The following 2 codes are used internally by CFITSIO:
  #define USHORT_IMG  20  /* 16-bit unsigned integers, equivalent to */
                          /*  BITPIX = 16, BSCALE = 1, BZERO = 32768 */
  #define ULONG_IMG   40  /* 32-bit unsigned integers, equivalent to */
                          /*  BITPIX = 32, BSCALE = 1, BZERO = 2147483648 */

Codes for the datatype of binary table columns and/or for the
datatype of variables when reading or writing keywords or data:

                              DATATYPE               TFORM CODE
  #define TBIT          1  /*                            'X' */
  #define TBYTE        11  /* 8-bit unsigned byte,       'B' */
  #define TLOGICAL     14  /* logicals (int)             'L' */
  #define TSTRING      16  /* ASCII string,              'A' */
  #define TSHORT       21  /* signed short,              'I' */
  #define TLONG        41  /* signed long,               'J' */
  #define TFLOAT       42  /* single precision float,    'E' */
  #define TDOUBLE      82  /* double precision float,    'D' */
  #define TCOMPLEX     83  /* complex (pair of floats)   'C' */
  #define TDBLCOMPLEX 163  /* double complex (2 doubles) 'M' */

  The following codes are used internally by CFITSIO:
  #define TINT         31  /* int                            */
  #define TUSHORT      20  /* unsigned short                 */
  #define TULONG       40  /* unsigned long                  */

HDU type code values (value returned when moving to new HDU):

  #define IMAGE_HDU  0  /* Primary Array or IMAGE HDU */
  #define ASCII_TBL  1  /* ASCII  table HDU */
  #define BINARY_TBL 2  /* Binary table HDU */

Column name and string matching case-sensitivity:

  #define CASESEN   1   /* do case-sensitive string match */
  #define CASEINSEN 0   /* do case-insensitive string match */

Logical states:

  #define TRUE 1
  #define FALSE 0