Re: [libvirt] [PATCH] maint: avoid spurious output if program not present
On 05/10/2010 02:19 PM, Eric Blake wrote:
Some shells warn about missing programs before redirection;
the idiomatic way to silence them is to run the program check
inside a subshell, with the redirections outside the subshell.
+++ b/cfg.mk
@@ -252,7 +252,7 @@ sc_prohibit_trailing_blank_lines:
preprocessor_exempt = (remote_(driver|protocol)\.h)$$
# Enforce recommended preprocessor indentation style.
sc_preprocessor_indentation:
- @if (cppi --version >/dev/null 2>&1); then \
+ @if (cppi --version) >/dev/null 2>&1; then \
Offlist, Jim reminded me that cfg.mk is only for developers with nice
environments, where we shouldn't need the subshell at all...
$(VC_LIST_EXCEPT) | grep '\.[ch]$$' \
| grep -vE '$(preprocessor_exempt)' | xargs cppi -a -c \
|| { echo '$(ME): incorrect preprocessor indentation' 1>&2; \
diff --git a/src/Makefile.am b/src/Makefile.am
index fe33cea..1542ab1 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -169,7 +169,7 @@ EXTRA_DIST += remote/remote_protocol.x remote/rpcgen_fix.pl
# * remove white space at end of buffer
.PHONY: remote_protocol-structs
remote_protocol-structs:
- $(AM_V_GEN)if pdwtags --help > /dev/null 2>&1; then \
+ $(AM_V_GEN)if (pdwtags --help) > /dev/null 2>&1; then \
But here, not only is Solaris /bin/sh noisy (which we are starting to
care less about these days, because it is so crufty), but so is FreeBSD
8.0 /bin/sh, which is a lot newer. And since it appears as part of the
user's Makefile, rather than development-specific, it should be silent.
Given that analysis, Jim gave the off-list ACK.
So I've kept the second hunk as-is, modified the first to drop the
subshell altogether, and pushed.
--
Eric Blake eblake(a)redhat.com +1-801-349-2682
Libvirt virtualization library http://libvirt.org
Attachments:
- signature.asc (application/pgp-signature — 619 bytes)