Configuration Information [Automatically generated, do not change]: Machine: i486 OS: linux-gnu Compiler: gcc Compilation CFLAGS: -DPROGRAM='bash' -DCONF_HOSTTYPE='i486' -DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i486-pc-linux-gnu' -DCONF_VENDOR='pc' -DLOCALEDIR='/usr/share/locale' -DPACKAGE='bash' -DSHELL -DHAVE_CONFIG_H -I. -I../bash -I../bash/include -I../bash/lib -g -O2 uname output: Linux fergus-warp.nyc.corp.google.com 2.6.18.5-gg26workstation-mixed64-32 #1 SMP Mon Feb 11 16:45:49 PST 2008 x86_64 GNU/Linux Machine Type: i486-pc-linux-gnu
Bash Version: 3.1 Patch Level: 17 Release Status: release Description: According to POSIX.1 (both 2004 <http://www.opengroup.org/onlinepubs/009695399/utilities/wait.html> and 2008 <http://www.opengroup.org/onlinepubs/9699919799/utilities/wait.html> versions), the "wait" command should wait until the process TERMINATES. (The exact wording is "If one or more pid operands are specified that represent known process IDs, the wait utility shall wait until all of them have terminated.") The POSIX.1 standard also describes the "-o monitor" option, and mentions nothing about it having any effect on the "wait" utility. But in bash, if the "-o monitor" option is set, the wait command finishes when the named process CHANGES STATUS, e.g. due to SIGSTOP or SIGCONT, rather than until it TERMINATES. In other words, when "-o monitor" is set, the observed behaviour of the wait command is like using the WUNTRACED and WCONTINUED options to waitpid(), whereas the wait command ought to behave like waitpid() _without_ those options. Repeat-By: #!/bin/bash set -o monitor sleep 5 & child1=$! (sleep 1; kill -STOP $child1; sleep 1; kill -CONT $child1) & child2=$! wait $child1 if [ $? == 147 ]; then echo "TEST FAILED: wait returned 147 (=128+SIGSTOP)" >&2 wait $child2 exit 1 else echo "TEST PASSED" fi This wait command should wait until the sleep process terminates, and then report its status as successful (0), so the script ought to print out "TEST PASSED". But instead the wait command terminates as soon as the sleep process gets the SIGSTOP signal, and returns 147 (i.e. 128 + SIGSTOP), so the test prints out "TEST FAILED".