Specifications

System Macros Invoked by Drivers
FORK
FORK
Creates a fork process for the context of the code to execute that follows this
macro invocation.
Format
FORK
Description
The FORK macro calls EXE$FORK to create a fork process. When the FORK
macro is invoked, the following registers must contain the values listed:
Register Contents
R3 Contents to be placed in R3 of the fork process
R4 Contents to be placed in R4 of the fork process
R5 Address of fork block
00(SP) Address of caller’s caller
Unlike EXE$IOFORK, EXE$FORK does not disable device timeouts by clearing
the UCB$V_TIM bit in the field UCB$L_STS.
Note
To avoid certain race conditions, this macro must be invoked at IPL3 or
higher.
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