gcc warning with hardening flags about pigz

[madler]

I put in a (void) to make it explicit that I consciously decided to ignore the return code. That should not generate a warning.

[Code7R]

And it should please also respect the LDFLAGS from environment. Proposal:

diff --git a/Makefile b/Makefile
index 6524ef3..f7f6191 100644
--- a/Makefile
+++ b/Makefile
@@ -1,6 +1,6 @@
 CC=cc
 CFLAGS=-O3 -Wall -Wextra
-LDFLAGS=-lz
+LDFLAGS+=-lz
 ZOPFLI=zopfli/src/zopfli/
 # use gcc and gmake on Solaris

[Code7R]

Sorry, (void) doesn't help here. I had to find a workaround in one of my projects for this check. Quote:

// STFU helpers, (void) casts are not effective for certain functions
static inline void ignore_value (int i) { (void) i; }
static inline void ignore_ptr (void* p) { (void) p; }

[madler]

You only got a warning for chown?

[madler]

Your suggestion for += in the Makefile is a different issue. You should create a new issue for that, and not mix it up with voided return codes.

[Code7R]

Yes, only this one. For example, see https://buildd.debian.org/status/fetch.php?pkg=pigz&arch=i386&ver=2.3.3-1&stamp=1422210364 .

Regarding += issue, that one is partially related, at least from my perspective. This style of value assignment (and gmake's lazy initialization rules) prevented the hardening flags from being passed. I used a workaround in the meantime (pushing CPPFLAGS/LDFLAGS/etc. from the make command line) and it's OK, so no new item related to that for now.

[madler]

Then it's a bug in the compiler. The behavior should be consistent with all of the other occurrences of voided return values, such as the chmod() and utimes() in the same routine, and the other dozen or more times int return values are voided in pigz.c. Either all of them should get the warning, or none of them should.