11/3/71 SYS SEEK (II)
NAME seek -- move read/write pointer
SYNOPSIS (file descriptor in r0)
sys seek; offset; ptrname / seek = 19.
DESCRIPTION The file descriptor refers to a file open for
reading or writing. The read (or write) pointer
for the file is set as follows:
if ptrname is 0, the pointer is set to offset.
if ptrname is 1, the pointer is set to its
current location plus offset.
if ptrname is 2, the pointer is set to the
size of the file plus offset.
FILES --
SEE ALSO tell
DIAGNOSTICS The error bit (c-bit) is set for an undefined
file descriptor.
BUGS A file can conceptually be as large as 2**20
bytes. Clearly only 2**16 bytes can be addressed
by seek. The problem is most acute on the tape
files and RK and RF. Something is going to be
done about this.
OWNER ken, dmr