| Message ID | 20171221225453.13158-3-aurelien@aurel32.net |
|---|---|
| State | New |
| Headers | show |
| Series | Fix wrong assumption about errno | expand |
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 >
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}. Many library functions can set @code{errno} to a nonzero value as a result of calling other library functions which might fail. You should