Hi Jon and Ian, On Wed, 14 Mar 2012 19:54:48 -0700, Ian Lance Taylor wrote: > Jonathan Andrews <jon@xxxxxxxxxxxxxxx> writes: > >> Would it be possible to add a warning to gcc C when code in an signal >> handler (alarm) uses non thread safe calls. > > Your request for a warning is reasonable, I just don't see a way to > implement it such that it is useful. I like that idea. When compiling applications on Apple's Mac OS X, they have keywords to inform about "deprecated" functions at compile-time. A similar solution might be possible, providing that the authors of the libraries and functions being called, mark those as "thread_safe" or "interrupt_safe". Ofcourse, a compiler might be able to recursively go through functions and hunt for things that identifies whether or not a function is thread-safe, a'la the optimizer, however at present, this might be too complex. It would, for instance be a bit difficult to see whether a function that writes to a shared memory location is thread-safe, because writing to this location *could* be a semaphore or behind a semaphore. Note: Remember there's a difference between thread-safe and interrupt-safe. Whether or not I should mention 'reentry-safe' or not, I don't know.. Well, hereby done. ;) Love, Jens
