Hello,
I have a little trouble using large objects with libpq an postgresql 8.2 in windows xp professional SP2.
I want to save and load large objects from/to database, but its fails.
If i try to use the lo_import() function
#define FILE_IN "d:/question-icon.png"
Oid file_oid = lo_import (conn, FILE_IN);
file_oid always have 0 value, nevertheless the large object has been created in table
pg_largeobject, but has no data.
If i try to create the large object by hand, read the file from disk, and then write the binary data
to the large object, the call to lo_write() always fail (always returns -1):
ifstream is;
is.open (FILE_IN, ios::binary );
// get length of file:
is.seekg (0, ios::end);
length = is.tellg();
is.seekg (0, ios::beg);
// allocate memory:
buffer = new char [length];
// read data as a block:
is.read (buffer,length);
is.close();
/*
* create the large object
*/
lobjId = lo_creat(conn, INV_WRITE);
if (lobjId == 0) {
fprintf(stderr, "no se pudo crear el objeto grande\n");
exit_nicely (conn);
}
lobj_fd = lo_open(conn, lobjId, INV_WRITE);
/*
* Write the content of the file to the large object
*/
tmp = lo_write(conn, lobj_fd, buffer, length);
if (tmp < length) {
fprintf(stderr, "error al escribir el objeto grande: %d bytes escritos\n", tmp);
exit_nicely (conn);
}
In this case, the call to lo_write() does not work, but i can see the large object created in table
pg_largeobject.
Any Idea?
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