Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

250 Chapter9

Intrinsics Reference (cont)

FREAD

Returns the record that was read. This structure

should be large enough to hold all of the information to

be transferred.

length 16-bit signed integer by value (required)

The number of halfwords or bytes to be transferred. If

this value is positive, it signiﬁes the length in

halfwords; if negative, in bytes. A zero indicates that no

transfer is to take place.

NOTE

Whether you specify the value of length as halfwords or bytes, the

actual physical transfer is done on a byte-by-byte basis for an

asynchronous device. If the number of bytes input exceeds the value

speciﬁed, the read will terminate on byte count.

Condition Codes

CCE The information was read.

CCG The logical end-of-data was encountered during

reading.

CCL The information was not read because an error

occurred: a terminal read was terminated by a special

character or timeout interval, as speciﬁed in the

FCONTROL intrinsic.

Additional Discussion

See Accessing Files Programmer’s Guide. See also discussion of IOWAIT

and IODONTWAIT in this manual.