gd_alter_spec(3)						      GETDATA							  gd_alter_spec(3)

NAME

       gd_alter_spec, gd_malter_spec -- modify a field in a dirfile

SYNOPSIS

       #include <getdata.h>

       int gd_alter_spec(DIRFILE *dirfile, const char *line, int recode);

       int gd_malter_spec(DIRFILE *dirfile, const char *line, const char *parent, int recode);

DESCRIPTION

       The gd_alter_spec() function modifies the field described by the field specification line in line to the dirfile specified by dirfile.  The
       gd_malter_spec() function behaves similarly, but modifies the metafield under the field indicated by the field code parent.  Field specifi-
       cation lines are described in detail in dirfile-format(5).

       The  name  of  the  field  to  be  modified,  which  must already exist, will be obtained from the field specification line.  When adding a
       metafield, line should only contain a field specification, and not a /META directive.

       If the modified field is of type RAW and the recode argument is non-zero, the binary file associated with the field will be  converted  for
       changes in data type and samples-per-frame.  If recode is zero, no binary file conversion will take place.

       If  the	modified field is of type LINTERP and the recode argument is non-zero, the look-up table file will be moved if entry->table speci-
       fies a different path, overwriting an existing file with the new pathname, if present.  If the field specified by  field_code  is  of  type
       other than RAW or LINTERP, the recode argument is ignored.

       Passing	these  functions a directive line instead of a field specification line will result in a syntax error.	These functions never call
       the registered parser callback function, even if line contains a syntax error.

RETURN VALUE

       On success, gd_alter_spec() and gd_malter_spec() return 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 in line was not found, or the parent field code was not found.

       GD_E_BAD_DIRFILE
	       The supplied dirfile was invalid.

       GD_E_FORMAT
	       A syntax error was encountered in line.

       GD_E_LINE_TOO_LONG
	       The  supplied  line was longer than the parser was able to deal with.  Lines are limited by the storage size of ssize_t.  On 32-bit
	       systems, this limits line to 2**31 bytes.  The limit is larger on 64-bit systems.

       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 at-
	       tempting to rename a LINTERP table file.

       GD_E_UNKNOWN_ENCODING
	       The encoding scheme of the indicated format specification fragment is not known to the library.	As a result, the library  was  un-
	       able to translate the binary file be associated with a modified RAW field.

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

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

SEE ALSO

       gd_alter_bit(3),  gd_alter_const(3),  gd_alter_entry(3),  gd_alter_lincom(3), gd_alter_linterp(3), gd_alter_multiply(3), gd_alter_phase(3),
       gd_alter_raw(3), gd_alter_spec(3), gd_metaflush(3), gd_open(3), gd_error(3), gd_error_string(3), dirfile-format(5)

Version 0.7.0							   21 July 2010 						  gd_alter_spec(3)