[PATCH] getgrnam.3: Add description of the functions are not thread-safe.

[PATCH] getgrnam.3: Add description of the functions are not thread-safe.

[Peng Haitao]

The functions getgrnam() and getgrgid() return a pointer to a static area which
is overwritten by a subsequent call to them. So they are thread-unsafe.

Signed-off-by: Peng Haitao <penght-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
---
 man3/getgrnam.3 |   15 ++++++++++++++-
 1 files changed, 14 insertions(+), 1 deletions(-)

diff --git a/man3/getgrnam.3 b/man3/getgrnam.3
index e4afa3e..cbbdc74 100644
--- a/man3/getgrnam.3
+++ b/man3/getgrnam.3
@@ -28,7 +28,7 @@
 .\" Modified 1993-07-24 by Rik Faith (faith-+5Oa3zvhR2o3uPMLIKxrzw@public.gmane.org)
 .\" Modified 2003-11-15 by aeb
 .\"
-.TH GETGRNAM 3 2010-10-21 "" "Linux Programmer's Manual"
+.TH GETGRNAM 3 2011-09-07 "" "Linux Programmer's Manual"
 .SH NAME
 getgrnam, getgrnam_r, getgrgid, getgrgid_r \- get group file entry
 .SH SYNOPSIS
@@ -199,6 +199,19 @@ Insufficient buffer space supplied.
 .TP
 .I /etc/group
 local group database file
+.SH ATTRIBUTES
+.SS Multithreading (see pthreads(7))
+The two functions
+.BR getgrnam ()
+and
+.BR getgrgid ()
+are not thread-safe.
+.LP
+The two functions
+.BR getgrnam_r ()
+and
+.BR getgrgid_r ()
+are thread-safe.
 .SH "CONFORMING TO"
 SVr4, 4.3BSD, POSIX.1-2001.
 .SH NOTES
-- 
1.7.1

-- 
Best Regards,
Peng Haitao

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Re: [PATCH] getgrnam.3: Add description of the functions are not thread-safe.

[Michael Kerrisk (man-pages)]

On Wed, Sep 7, 2011 at 3:13 AM, Peng Haitao <penght-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org> wrote:
>
> The functions getgrnam() and getgrgid() return a pointer to a static area which
> is overwritten by a subsequent call to them. So they are thread-unsafe.

I've applied this patch.

Thanks,

Michael


> Signed-off-by: Peng Haitao <penght-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
> ---
>  man3/getgrnam.3 |   15 ++++++++++++++-
>  1 files changed, 14 insertions(+), 1 deletions(-)
>
> diff --git a/man3/getgrnam.3 b/man3/getgrnam.3
> index e4afa3e..cbbdc74 100644
> --- a/man3/getgrnam.3
> +++ b/man3/getgrnam.3
> @@ -28,7 +28,7 @@
>  .\" Modified 1993-07-24 by Rik Faith (faith-+5Oa3zvhR2o3uPMLIKxrzw@public.gmane.org)
>  .\" Modified 2003-11-15 by aeb
>  .\"
> -.TH GETGRNAM 3 2010-10-21 "" "Linux Programmer's Manual"
> +.TH GETGRNAM 3 2011-09-07 "" "Linux Programmer's Manual"
>  .SH NAME
>  getgrnam, getgrnam_r, getgrgid, getgrgid_r \- get group file entry
>  .SH SYNOPSIS
> @@ -199,6 +199,19 @@ Insufficient buffer space supplied.
>  .TP
>  .I /etc/group
>  local group database file
> +.SH ATTRIBUTES
> +.SS Multithreading (see pthreads(7))
> +The two functions
> +.BR getgrnam ()
> +and
> +.BR getgrgid ()
> +are not thread-safe.
> +.LP
> +The two functions
> +.BR getgrnam_r ()
> +and
> +.BR getgrgid_r ()
> +are thread-safe.
>  .SH "CONFORMING TO"
>  SVr4, 4.3BSD, POSIX.1-2001.
>  .SH NOTES
> --
> 1.7.1
>
> --
> Best Regards,
> Peng Haitao
>



-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface"; http://man7.org/tlpi/
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