I'm building some code with clang. Here's a cut-down version of what I'm doing. (Please bear in mind that during the cutting-down process, I've cut out every irrelevant detail I can, including anything that might make it obvious why I might actually want to do this.)
push.h:
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpragma-pack"
#pragma pack(push)
#pragma pack(1)
pop.h:
#pragma pack(pop)
#pragma GCC diagnostic pop
main.c:
#include "push.h"
struct Fred {char x;};
#include "pop.h"
Compile it like this:
clang -Wall -pedantic -c main.c
Doing this, I get a warning:
tmbp ~/tmp/pushpack % clang -Wall -pedantic -c main.c
main.c:3:10: warning: the current #pragma pack aligment value is modified in the included file [-Wpragma-pack]
#include "pop.h"
^
note: previous '#pragma pack' directive that modifies alignment is here
1 warning generated.
tmbp ~/tmp/pushpack %
How can I suppress this warning in this case? I'd like to do this by adding something to pop.h, if possible.
I don't really want to suppress the warning globally, because it seems like it might be kind of useful in the long run (even if not when I'm including push.h and pop.h).
I don't want to add additional junk to every include of pop.h, because in my non-cut-down actual program, because there's tons of them.
I don't want to have just a naked #pragma pack(pop) instead, because I'd prefer things to be symmetrical.
I don't want to make them symmetrical by inlining the contents of push.h, because in practice there's a bit more to it than is shown here.
What, if any, are my options?
Clang version: (this is the one that comes with Xcode 10 - don't think this warning was there in Xcode 9)
tmbp ~/tmp/pushpack % clang --version
Apple LLVM version 10.0.0 (clang-1000.11.45.2)
Target: x86_64-apple-darwin17.7.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
You cannot restore the warning options in pop.h if you don't want to see the warning generated for main.c resulting from including pop.h. Restore the warning options after `#include "pop.h".