Hello Trevor, On Thu, Sep 16, 2010 at 6:44 PM, W. Trevor King <wking@xxxxxxxxxx> wrote: > The glibc manual section on initstate > http://www.gnu.org/software/libc/manual/html_node/BSD-Random.html#index-initstate-2292 > makes no mention of NULL on error (which it does mention for setstate). > > As proof, the test code > > #include <stdlib.h> > #include <stdio.h> > #include <errno.h> > > int main(int argc, char **argv) > { > void *state = NULL; > int arg_state = 0; > > printf("errno before %d\n", errno); > state = (void *) initstate(1, (void *) &arg_state, 7); > printf("errno after %d (EINVAL is %d)\n", errno, EINVAL); > printf("state returned from bad initstate call: %p\n", state); > > return 0; > } > > returns > > errno before 0 > errno after 22 (EINVAL is 22) > state returned from bad initstate call: 0xb781f040 > > not > > errno before 0 > errno after 22 (EINVAL is 22) > state returned from bad initstate call: (nil) > > This makes sense because glibc's stdlib/random.c defines __initstate() > to always return ostate (blank lines removed): > > char * > __initstate (seed, arg_state, n) > unsigned int seed; > char *arg_state; > size_t n; > { > int32_t *ostate; > __libc_lock_lock (lock); > ostate = &unsafe_state.state[-1]; > __initstate_r (seed, arg_state, n, &unsafe_state); > __libc_lock_unlock (lock); > return (char *) ostate; > } > > Personally, I think the behavior specified by the old man page makes > more sense, but I don't imagine the glibc folks want to change their > version. > > This patch it against the current Git version of man-pages, and was > generated with 'git format-patch -1' before I altered it to include > the extra information the man-pages project suggested: > http://www.kernel.org/doc/man-pages/patches.html > > W. Trevor King Thanks for the detailed report. I applied the patch for man-pages-3.27. Thanks, Michael > --- > man3/random.3 | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/man3/random.3 b/man3/random.3 > index 7568dc1..6845b98 100644 > --- a/man3/random.3 > +++ b/man3/random.3 > @@ -120,9 +120,10 @@ The > function returns no value. > The > .BR initstate () > -and > +function returns a pointer to the previous state. > +The > .BR setstate () > -functions return a pointer to the previous state > +function returns a pointer to the previous state > array, or NULL on error. > .SH ERRORS > .TP > -- > 1.7.2.2.173.g515cc > -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Author of "The Linux Programming Interface"; http://man7.org/tlpi/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
