Daniel Shahaf <d...@daniel.shahaf.name> writes: > Philip Martin wrote on Thu, Oct 13, 2011 at 18:44:44 +0100: >> Daniel Shahaf <d...@daniel.shahaf.name> writes: >> >> > First of all, I made the same patch yesterday elsewhere. >> >> Another bug :) >> >> > Second of all, the use is #if, not #ifdef, so I believe the macro is >> > always defined (to 0 or 1). >> >> The one doesn't follow from the other. In either case the macro could >> be zero, non-zero, no value or not defined: >> >> #if #ifdef >> #define APR_HAS_THREADS 1 true true >> #define APR_HAS_THREADS 0 false true >> #define APR_HAS_THREADS true true >> <nothing> false false >> > > Is this standard behaviour?
I believe so. > >> So not defining APR_HAS_THREADS is a valid way to define no thread >> support, but it means you can't use APR_HAS_THREADS directly as a >> variable. >> >> It's possible that APR will always ensure that APR_HAS_THREADS is either >> 0 or 1, but the C language does not. >> > > My reading of > http://svn.apache.org/repos/asf/apr/apr/tags/0.9.0/include/apr.h.in > http://svn.apache.org/repos/asf/apr/apr/tags/0.9.0/include/apr.hnw > http://svn.apache.org/repos/asf/apr/apr/tags/0.9.0/include/apr.hw > is that APR_HAS_THREADS is always defined. Then we would be relying on APR to do it. It's not the way all preprocessor symbols are defined, for example svn_private_config.h generally uses <nothing> rather than #define XXX 0 and APR does the same for APR_IS_DEV_VERSION. -- uberSVN: Apache Subversion Made Easy http://www.uberSVN.com
