1 # $NetBSD: varmod-assign-shell.mk,v 1.11 2025/01/11 21:21:33 rillig Exp $ 2 # 3 # Tests for the variable modifier '::!=', which assigns the output of a shell 4 # command to the variable, but only if the command exited successfully. This 5 # is different from the other places that capture the output of an external 6 # command (variable assignment operator '!=', expression modifier ':sh', 7 # expression modifier ':!...!'), which also use the output when the shell 8 # command fails or crashes. 9 # 10 # The variable modifier '::!=' and its close relatives have been around since 11 # var.c 1.45 from 2000-06-01. 12 # 13 # Before 2020.08.25.21.16.53, the variable modifier '::!=' had a bug for 14 # unsuccessful commands, it put the previous value of the variable into the 15 # error message instead of the command that was executed. That's where the 16 # counterintuitive error message 'make: "previous" returned non-zero status' 17 # comes from. 18 19 DIRECT= previous 20 # expect+1: warning: Command "echo output; (exit 13)" exited with status 13 21 DIRECT!= echo output; (exit 13) 22 23 ASSIGNED= previous 24 .MAKEFLAGS: -dv # to see the "Capturing" debug output 25 # expect+1: warning: Command "echo output; (exit 13)" exited with status 13 26 _:= ${ASSIGNED::!=echo output; ${:U(exit 13)}} 27 .MAKEFLAGS: -d0 28 29 all: 30 @echo DIRECT=${DIRECT:Q} 31 @echo ASSIGNED=${ASSIGNED:Q} 32
Indexes created Sat Sep 20 22:09:52 GMT 2025