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  -1
       and sets the dirfile error 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_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 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).

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.

SEE ALSO

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