next up previous contents FITSIO Home
Next: 6.4.8 Delete Keyword Subroutines Up: 6.4 FITS Header I/O Previous: 6.4.6 Modify Keyword Subroutines   Contents


6.4.7 Update Keyword Subroutines

1
Update an 80-character record in the CHU. If the specified keyword already exists then that header record will be replaced with the input CARD string. If it does not exist then the new record will be added to the header. The FTUKLS subroutine works the same as the FTUKYS subroutine, except it also supports long string values greater than 68 characters in length.

        FTUCRD(unit,keyword,card, > status)

2
Update the value and comment fields of a keyword in the CHU. The specified keyword is modified if it already exists (by calling FTMKYx) otherwise a new keyword is created by calling FTPKYx. The E and D versions of this routine have the added feature that if the 'decimals' parameter is negative, then the 'G' display format rather then the 'E' format will be used when constructing the keyword value, taking the absolute value of 'decimals' for the precision. This will suppress trailing zeros, and will use a fixed format rather than an exponential format, depending on the magnitude of the value.

        FTUKY[JKLS](unit,keyword,keyval,comment, > status)
        FTUKLS(unit,keyword,keyval,comment, > status)
        FTUKY[EDFG](unit,keyword,keyval,decimals,comment, > status)

3
Update the value of an existing keyword to be undefined, or null, or insert a new undefined-value keyword if it doesn't already exist. The value string of the keyword is left blank in this case.

        FTUKYU(unit,keyword,comment, > status)


next up previous contents FITSIO Home
Next: 6.4.8 Delete Keyword Subroutines Up: 6.4 FITS Header I/O Previous: 6.4.6 Modify Keyword Subroutines   Contents