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dirfile_alter_const

NAME

dirfile_alter_bit, dirfile_alter_const, dirfile_alter_lincom, dirfile_alter_linterp, dirfile_alter_multiply, dirfile_alter_phase, dirfile_alter_raw --- modify a field in a dirfile

SYNOPSIS

#include <getdata.h>

int dirfile_alter_bit(DIRFILE *dirfile, const char *field_code, const char *in_field, int bitnum, int numbits);

int dirfile_alter_const(DIRFILE *dirfile, const char *field_code, gd_type_t const_type);

int dirfile_alter_lincom(DIRFILE *dirfile, const char *field_code, int n_fields, const char **in_fields, const double *m, const double *b);

int dirfile_alter_linterp(DIRFILE *dirfile, const char *field_code, const char *in_field, const char *table, int rename_table);

int dirfile_alter_multiply(DIRFILE *dirfile, const char *field_code, const char *in_field1, const char *in_field2);

int dirfile_alter_phase(DIRFILE *dirfile, const char *field_code, const char *in_field, int phase);

int dirfile_alter_raw(DIRFILE *dirfile, const char *field_code, gd_type_t data_type, unsigned int spf, int recode);

DESCRIPTION

These functions provide alternatives to using the dirfile_alter_entry(3) function to modify a field of the indicated type in the dirfile specified by dirfile.

In all of these calls, field_code indicates the the field to be modified, which may be a regular field, or a metafield specified by its full (slashed) field code. The meaning and valid types of other arguments may be obtained from the get_entry(3) and dirfile-format(5) manual pages.

The dirfile_alter_lincom() function takes pointers to three arrays of length n_fields containing the input field names (in_fields), the gain factors (m), and the offset terms (b).

Some field parameters have special values which indicate no change should be made to the parameter. Specifically, if any of the string parameters or m or b are NULL, the old values will be retained. Similarly, if spf, n_fields, or numbits is zero, or if bitnum is -1, or if data_type, or const_type are equal to GD_NULL, these parameters will not be modified.

All fields added with this interface must contain numerical parameters. Fields with CONST fields as parameters cannot be added with these functions. Those fields must be added with dirfile_alter_spec(3).

If rename_table is non-zero, the look-up table referenced by the LINTERP field will be renamed to the path given by table. If recode is non-zero, the binary file associated with the RAW field will be re-encoded to reflect the new field parameters.

RETURN VALUE

On success, any of these functions returns zero. On error, -1 is returned and the dirfile error is set to a non-zero error value. Possible error values are:

GD_E_ACCMODE

The specified dirfile was opened read-only.

GD_E_ALLOC

The library was unable to allocate memory.

GD_E_BAD_CODE

The field specified by field_code was not found.

GD_E_BAD_DIRFILE

The supplied dirfile was invalid.

GD_E_BAD_ENTRY

One or more of the field parameters specified was invalid.

GD_E_BAD_FIELD_TYPE

The field specified by field_code was of the wrong type for the function called.

GD_E_BAD_TYPE

The data_type or const_type argument was invalid.

GD_E_PROTECTED

The metadata of the fragment was protected from change. Or, a request to translate the binary file associated with a RAW field was attempted, but the data of the fragment was protected.

GD_E_RAW_IO

An I/O error occurred while translating the binary file associated with a modified RAW field, or an I/O error occurred while attempting to rename a LINTERP table file.

GD_E_UNKNOWN_ENCODING

The encoding scheme of the specified format file fragment is not known to the library. As a result, the library was unable to translate the binary file be associated with a modified RAW field.

GD_E_UNSUPPORTED

The encoding scheme of the specified format file fragment does not support translating the empty binary file associated with a modified RAW field.

The dirfile error may be retrieved by calling get_error(3). A descriptive error string for the last error encountered can be obtained from a call to get_error_string(3).

SEE ALSO

dirfile_alter_entry(3), dirfile_alter_spec(3), dirfile_malter_spec(3), dirfile_metaflush(3), dirfile_open(3), get_error(3), get_error_string(3), dirfile-format(5)