NAME

       gd_alter_endianness — modify the byte sex of fields in a Dirfile

SYNOPSIS

       #include <getdata.h>

       int gd_alter_endianness(DIRFILE *dirfile, unsigned long byte_sex, int fragment_index, int
              recode);

DESCRIPTION

       The gd_alter_endianness() function sets the byte sex of the format specification  fragment
       given  by fragment_index to byte_sex in the dirfile(5) database specified by dirfile.  The
       byte sex of a fragment indicate the endianness of data stored in binary  files  associated
       with  RAW fields defined in the specified fragment.  The byte sex of a fragment containing
       no RAW fields is ignored.

       The byte_sex argument should be one of the following:

       0 (zero)
               Indicating that the byte  sex  should  be  the  native  endianness  of  the  host,
               whichever that may be.

       GD_BIG_ENDIAN
               Indicating that the byte sex should be big endian.

       GD_LITTLE_ENDIAN
               Indicating that the byte sex should be little endian.

       (GD_BIG_ENDIAN | GD_LITTLE_ENDIAN)
               Indicating  that  the  byte sex should be the opposite of the native endianness of
               the host, whichever that may be.

       Furthermore, any of these may be bitwise  or'd  with  GD_ARM_ENDIAN  or  GD_NOT_ARM_ENDIAN
       indicating that the floating point data are stored in the ARM middle-endian format.

       In addition to being simply a valid fragment index, fragment_index may also be the special
       value GD_ALL_FRAGMENTS, which indicates that the byte sex of all fragments in the database
       should be changed.

       If  the  recode argument is non-zero, this call will byte swap the binary data of affected
       RAW fields to account for the change in byte sex.  If the  encoding  of  the  fragment  is
       endianness  insensitive,  or if the data type is only one byte in size, no change is made.
       The I/O pointer of all affected RAW fields is reset to the beginning-of-frame.

       If recode is zero, affected binary files are left untouched.

RETURN VALUE

       Upon successful completion, gd_alter_endianness() returns zero.  On error,  it  returns  a
       negative-valued error code.  Possible error codes are:

       GD_E_ACCMODE
               The specified dirfile was opened read-only.

       GD_E_ALLOC
               The library was unable to allocate memory.

       GD_E_ARGUMENT
               The supplied byte_sex was invalid.

       GD_E_BAD_DIRFILE
               The supplied dirfile was invalid.

       GD_E_BAD_INDEX
               The supplied index was out of range.

       GD_E_IO An I/O error occurred while attempting to byte swap a binary file.

       GD_E_PROTECTED
               The  metadata  of  the  indicated format specification fragment was protected from
               change, or the binary data of the fragment was protected from  change  and  binary
               file byte swapping was requested.

       GD_E_UNCLEAN_DB
               An error occurred while moving the byte-swapped file into place.  As a result, the
               database may be in an unclean state.  See the NOTES  section  below  for  recovery
               instructions.   In  this  case, the dirfile will be flagged as invalid, to prevent
               further database corruption.  It should be immediately closed.

       GD_E_UNKNOWN_ENCODING
               The encoding scheme of the fragment is unknown.

       GD_E_UNSUPPORTED
               The encoding scheme of the fragment does not support binary file byte swapping.

       The error code is also stored in the DIRFILE  object  and  may  be  retrieved  after  this
       function  returns by calling gd_error(3).  A descriptive error string for the error may be
       obtained by calling gd_error_string(3).

NOTES

       A binary file byte swap occurs out-of-place.   As  a  result,  sufficient  space  must  be
       present  on  the  filesystem  for  the binary files of all RAW fields in the fragment both
       before  and  after  translation.    If   all   fragments   are   updated   by   specifying
       GD_ALL_FRAGMENTS, the byte swapping occurs one fragment at a time.

       An  error code of GD_E_UNCLEAN_DB indicates a system error occurred while moving the byte-
       swapped binary data into place or when deleting  the  old  data.   If  this  happens,  the
       database may be left in an unclean state.  The caller should check the filesystem directly
       to ascertain the state of the dirfile data before continuing.  For recovery  instructions,
       see the file /usr/share/doc/getdata/unclean_database_recovery.txt.

HISTORY

       The function dirfile_alter_endianness() appeared in GetData-0.5.0.

       In GetData-0.7.0, this function was renamed to gd_alter_endianness().  The GD_E_ARM_ENDIAN
       and GD_NOT_ARM_ENDIAN flags also appeared in this version.

       in GetData-0.10.0, the error return from this function changed  from  -1  to  a  negative-
       valued error code.

SEE ALSO

       gd_open(3),   gd_error(3),   gd_error_string(3),  gd_endianness(3),  dirfile(5),  dirfile-
       format(5)