When configuring bash on a self-hosted QNX 6.6 or QNX7 system: This is an OS that has /dev/stdin and friends, but does not have /dev/fd.
When blind cross-compiling bash for QNX, one would get a guess answer of: bash_cv_dev_fd=standard bash_cv_dev_stdin=present When doing the safer self-hosted native configure, we get several significant improvements, but also: bash_cv_dev_fd=absent bash_cv_dev_stdin=absent When "the truth" for QNX should really be (we think): bash_cv_dev_fd=absent bash_cv_dev_stdin=present The odd configure output is due to the test having the presence of /dev/stdin guarded by testing for the existence of /dev/fd or /dev/self/fd: if *test -d /dev/fd* && (exec test -r /dev/stdin < /dev/null) ; then bash_cv_dev_stdin=present elif *test -d /proc/self/fd* && (exec test -r /dev/stdin < /dev/null) ; then bash_cv_dev_stdin=present else bash_cv_dev_stdin=absent fi At first glance it appears that: lib/sh/eaccess.c redir.c are the only consumers of HAVE_DEV_STDIN, and that the code so guarded would function in the absence of HAVE_DEV_FD. So, can those in the know weigh in on which interpretation below is correct: (a) The DEV_STDIN code block isn't relevant unless you're in the presence of DEV_FD, so it's harmless and appropriate to have the current configure output. (b) The dependency is there for good reason, and we're missing what will break in the presence of DEV_FD=no + DEV_STDIN=yes (c) There is a some other pathological environment where bash wants the DEV_STDIN code disabled when DEV_FD isn't there, and we should refine this test in our patch to further distinguish QNX from the environment that created the test w/ DEV_FD to DEV_STDIN dependency. (d) The DEV_FD -> DEV_STDIN dependency should be removed from the test completely, as a patch for all environments? Thanks! P.S. For completeness: # uname -a QNX localhost 6.6.0 2014/02/22-18:29:34EST x86pc x86 # bash -version GNU bash, version 4.3.48(1)-release (i486-pc-nto-qnx6.6.0) # uname -a QNX localhost 7.0.0 2017/02/14-16:01:20EST x86pc x86_64 # bash -version GNU bash, version 4.3.48(1)-release (x86_64-pc-nto-qnx7.0.0)
