The POSIX API always stops at first NUL so there's no change for that. The BSD REG_STARTEND API, with its explicit range, can include NULs within that range, and those NULs are matched with . and [^]. Heretofor, for a string of "a\0c", glibc would match "[^q]c", but not ".c". This is both inconsistent and nonconformant to BSD REG_STARTEND. With this patch, they're identical like you'd expect, and the tst-reg-startend.c: ..c: a^@c: no match$ failure is removed. Another approach would be to remove it from _RE_SYNTAX_POSIX_COMMON, but it's unclear to me what the custody chain is like for that and what other regex APIs glibc offers that could be affected by this. Signed-off-by: Ahelenia Ziemiańska --- Please keep me in CC, as I'm not subscribed. posix/regcomp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/posix/regcomp.c b/posix/regcomp.c index 647b18ba9e..cbd9bfc673 100644 --- a/posix/regcomp.c +++ b/posix/regcomp.c @@ -462,7 +462,7 @@ regcomp (regex_t *__restrict preg, const char *__restrict pattern, int cflags) { reg_errcode_t ret; reg_syntax_t syntax = ((cflags & REG_EXTENDED) ? RE_SYNTAX_POSIX_EXTENDED - : RE_SYNTAX_POSIX_BASIC); + : RE_SYNTAX_POSIX_BASIC) & ~RE_DOT_NOT_NULL; preg->buffer = NULL; preg->allocated = 0; -- 2.30.2