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6.4.6 Modify Keyword Subroutines

Wild card characters, as described in the Read Keyword section, above, may be used when specifying the name of the keyword to be modified.

1
Modify (overwrite) the nth 80-character header record in the CHU

        FTMREC(unit,key_no,card, > status)

2
Modify (overwrite) the 80-character header record for the named keyword in the CHU. This can be used to overwrite the name of the keyword as well as its value and comment fields.

        FTMCRD(unit,keyword,card, > status)

3
Modify (overwrite) the name of an existing keyword in the CHU preserving the current value and comment fields.

        FTMNAM(unit,oldkey,keyword, > status)

4
Modify (overwrite) the comment field of an existing keyword in the CHU

        FTMCOM(unit,keyword,comment, > status)

5
Modify the value and comment fields of an existing keyword in the CHU. The FTMKLS subroutine works the same as the FTMKYS subroutine, except it also supports long string values greater than 68 characters in length. Optionally, one may modify only the value field and leave the comment field unchanged by setting the input COMMENT parameter equal to the ampersand character (&). 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.

        FTMKY[JKLS](unit,keyword,keyval,comment, > status)
        FTMKLS(unit,keyword,keyval,comment, > status)
        FTMKY[EDFG](unit,keyword,keyval,decimals,comment, > status)

6
Modify the value of an existing keyword to be undefined, or null. The value string of the keyword is set to blank. Optionally, one may leave the comment field unchanged by setting the input COMMENT parameter equal to the ampersand character (&).

        FTMKYU(unit,keyword,comment, > status)


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Next: 6.4.7 Update Keyword Subroutines Up: 6.4 FITS Header I/O Previous: 6.4.5 Read Keyword Subroutines   Contents