gd_alter_endianness(3) GETDATA gd_alter_endianness(3)NAMEgd_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 frag‐
ment 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 na‐
tive 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. If recode is zero,
affected binary files are left untouched.
RETURN VALUE
Upon successful completion, gd_alter_endianness() returns zero. On er‐
ror, it returns -1 and sets the dirfile error to a non-zero error val‐
ue. 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_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 re‐
quested.
GD_E_RAW_IO
An I/O error occurred while attempting to byte swap a binary
file.
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 fur‐
ther 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 descrip‐
tive 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 frag‐
ments are updated by specifying GD_ALL_FRAGMENTS, the byte swapping oc‐
curs 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 instruc‐
tions, see the file /usr/share/doc/getdata/unclean_database_recov‐
ery.txt.
SEE ALSOgd_open(3), gd_error(3), gd_error_string(3), gd_endianness(3),
dirfile(5), dirfile-format(5)Version 0.8.0 1 January 2012 gd_alter_endianness(3)
