pg_lo_read

pg_lo_read
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pg_lo_read — Read from a large object

Synopsis

pg_lo_read conn descriptor bufVar len

Description

pg_lo_read reads at most len bytes from a large object into a variable named bufVar.

Arguments

conn: The handle of the connection.
descriptor: A descriptor for the large object from pg_lo_open.
bufVar: The name of a buffer variable to contain the large object segment.
len: The maximum number of bytes to read.

Return Value

The number of bytes actually read is returned; this could be less than the number requested if the end of the large object is reached first.

If an error occurs reading from the large object, a negative number will be returned. Other errors result in a Tcl error being thrown. Note that error handling for this command is different from most of the other Large Object commands.

Notes

All large object manipulation must take place within an SQL transaction block.

This command uses or emulates the PostgreSQL libpq function lo_read.

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