[Qemu-devel] Re: [PATCH] scripts: add a guard macro in generated .h files
On 02/21/2011 07:42 AM, Tristan Gingold wrote: Mostly a style issue. It is common to always protect header files against multiple inclusion, unless the header is meant to be included several times (which is not the case for these config files). I think this is a good practice. Traditionally, autoconf's config.h headers have no guards either. This can indeed cause some troubles. However, it also helps highlighting poor practices, such as libraries installing a config.h file including it from a public header. I once got redefinition warnings for macros in config-host.h, but I agree that adding the guard macro doesn't fix this issue. config-host.h should always be the first included header (we are poor at this) and its macros should never conflict with anything else. I think we should rather fix the problems you've seen with config-host.h, if you can still reproduce them. Paolo
[Qemu-devel] Re: [PATCH] scripts: add a guard macro in generated .h files
On Feb 21, 2011, at 9:14 AM, Paolo Bonzini wrote: On 02/21/2011 07:42 AM, Tristan Gingold wrote: Mostly a style issue. It is common to always protect header files against multiple inclusion, unless the header is meant to be included several times (which is not the case for these config files). I think this is a good practice. Traditionally, autoconf's config.h headers have no guards either. This can indeed cause some troubles. However, it also helps highlighting poor practices, such as libraries installing a config.h file including it from a public header. I once got redefinition warnings for macros in config-host.h, but I agree that adding the guard macro doesn't fix this issue. config-host.h should always be the first included header (we are poor at this) and its macros should never conflict with anything else. I think we should rather fix the problems you've seen with config-host.h, if you can still reproduce them. Thank you. I will investigate the next time I have the issue and the time. Tristan.
