Am Donnerstag, dem 11.07.2024 um 11:35 +0200 schrieb Alejandro Colomar via Gcc: > Hi, > > I was wondering how we could extend attributes such as gnu::access() to > apply it to pointees too. Currently, there's no way to specify the > access mode of a pointee. > > Let's take for example strsep(3): > > With current syntax, this is what we can specify: > > [[gnu::access(read_write, 1)]] > [[gnu::access(read_only, 2)]] > [[gnu::nonnull(1, 2)]] > [[gnu::null_terminated_string_arg(2)]] > char * > strsep(char **restrict sp, const char *delim);
The main problem from a user perspective is that these are attributes on the function declaration and not on the argument (type). > > I was thinking that with floating numbers, one could specify the number > of dereferences with a number after the decimal point. It's a bit > weird, since the floating point is interpreted as two separate integer > numbers separated by a '.', but could work. In this case: > > [[gnu::access(read_write, 1)]] > [[gnu::access(read_write, 1.1)]] > [[gnu::access(read_only, 2)]] > [[gnu::nonnull(1, 2)]] > [[gnu::null_terminated_string_arg(1.1)]] > [[gnu::null_terminated_string_arg(2)]] > char * > strsep(char **restrict sp, const char *delim); > > Which would mark the pointer *sp as read_write and a string. What do > you think about it? If the attributes could be applied to the type, then one could attach them directly at an intermediate pointer level, which would be more intuitive and less fragile. Martin
