User guide

3.2. GLOBAL VARIABLES 43

modules hold the relocatable byte stream interpretive code used by all BCPL interpre-

tive systems. Constants with names ending with 64 are used in the 64-bit version of

Cintcode. For more details, see the description of loadseg on page 68.

tickspersecond CIN:y, POS:y, NAT:n

This constant no longer exists since time is now measured i n milli-seconds (and dates

in days). In both Cintsys and Cintpos, delays measured in milli-seconds can be achieved

using delay(msecs) and delays until a speciﬁed absolute time can be done using

delayuntil(days, msecs). Under Cintpos, the clock dev i ce now takes packets that

specify absolute times (in days since 1 January 1970 and milli-second since midnight)

for their release. For example, sendpkt(notinuse, -1, 0, 0, 0, days, msecs) will

resume executi on when the time speciﬁed by days and msecs is reached. The second

argument (-1) spe ci ﬁ es the clock device.

timeoutch CIN:n, POS:y, NAT:n

This is the value returned by rdch when a timeout occurs while trying to read from

a stream. Its value is normally -2. Cur r ently only TCP streams under Cintpos provide

the timeout mechani s m.

ug CIN:y, POS:y, NAT:y

This constant speciﬁed the ﬁrst Global variable avail abl e to user programs. Cur-

rently ug=200 so globals below this value are reserved for system use and the standard

library. Since ug may change it would be wise to use it.

3.2 Global Vari a bl es

This section describes the global variables declared in libhdr.h.

cis, cos CIN:y, POS:y, NAT:y

These are, respectively, the currently selected input and output streams. Zero

indicates that no stream is selected.

colist CIN:n, POS:y, NAT:n

This holds the list of currently existing coroutines.

consoletask CIN:n, POS:y, NAT:n

This is a variable used by command language interpreters.

currco CIN:n, POS:y, NAT:n

This points to the currently executing coroutine.

currentdir CIN:n, POS:y, NAT:n

This is a string holding the name of the current working direct or y.

globsize CIN:y, POS:y, NAT:y

This variable is in global zero and holds the size of the global vector. Its value is

normally 1000.