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Re: [PATCH 2/3] manual: clarify errno value on success [BZ #22615]
On 12/21/2017 02:54 PM, Aurelien Jarno wrote:
> The current glibc manual is ambiguous about the errno value on success
> and suggests that it is left unchanged. Some functions might and
> sometimes do change the errno value, however they never set it to 0.
>
> This patch clarifies this section of the manual.
>
> Changelog:
> [BZ #22615]
> * manual/errno.texi (Checking for Errors): Explicitly say that errno
> might be set on success.
OK.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> ---
> ChangeLog | 6 ++++++
> manual/errno.texi | 12 ++++++------
> 2 files changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/ChangeLog b/ChangeLog
> index cb41a07a25..7bf30d27ef 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,9 @@
> +2017-12-21 Aurelien Jarno <aurelien@aurel32.net>
> +
> + [BZ #22615]
> + * manual/errno.texi (Checking for Errors): Explicitly say that errno
> + might be set on success.
> +
> 2017-12-21 Aurelien Jarno <aurelien@aurel32.net>
>
> [BZ #22611]
> diff --git a/manual/errno.texi b/manual/errno.texi
> index 3e0b862c4e..eaac8e6dca 100644
> --- a/manual/errno.texi
> +++ b/manual/errno.texi
> @@ -50,12 +50,12 @@ possibility except when writing signal handlers.
> The initial value of @code{errno} at program startup is zero. Many
> library functions are guaranteed to set it to certain nonzero values
> when they encounter certain kinds of errors. These error conditions are
> -listed for each function. These functions do not change @code{errno}
> -when they succeed; thus, the value of @code{errno} after a successful
> -call is not necessarily zero, and you should not use @code{errno} to
> -determine @emph{whether} a call failed. The proper way to do that is
> -documented for each function. @emph{If} the call failed, you can
> -examine @code{errno}.
> +listed for each function. These functions never set @code{errno} to zero
> +and might set it to a non-zero value when they succeed; thus, the value of
> +@code{errno} after a successful call is not necessarily zero, and you
> +should not use @code{errno} to determine @emph{whether} a call failed.
> +The proper way to do that is documented for each function. @emph{If} the
> +call failed, you can examine @code{errno}.
OK.
>
> Many library functions can set @code{errno} to a nonzero value as a
> result of calling other library functions which might fail. You should
>
--
Cheers,
Carlos.