[PATCH] popen.3: RETURN VALUE: describe successful case

[PATCH] popen.3: RETURN VALUE: describe successful case

[Nikola Forró]

Reference:
http://pubs.opengroup.org/onlinepubs/9699919799/functions/popen.html
http://pubs.opengroup.org/onlinepubs/9699919799/functions/pclose.html

Signed-off-by: Nikola Forró <nforro-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 man3/popen.3 | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/man3/popen.3 b/man3/popen.3
index f075581..bafa42c 100644
--- a/man3/popen.3
+++ b/man3/popen.3
@@ -123,17 +123,18 @@ function waits for the associated process to terminate and returns the exit
 status of the command as returned by
 .BR wait4 (2).
 .SH RETURN VALUE
-The
-.BR popen ()
-function returns NULL if the
+.BR popen ():
+on success, returns a pointer to an open stream that
+can be used to read or write to the pipe;
+if the
 .BR fork (2)
 or
 .BR pipe (2)
-calls fail, or if it cannot allocate memory.
-.PP
-The
-.BR pclose ()
-function returns \-1 if
+calls fail, or if the function cannot allocate memory,
+NULL is returned.
+
+.BR pclose ():
+on success, returns the exit status of the command; if
 .\" These conditions actually give undefined results, so I commented
 .\" them out.
 .\" .I stream
@@ -141,10 +142,12 @@ function returns \-1 if
 .\".I stream
 .\" already "pclose()d", or if
 .BR wait4 (2)
-returns an error, or some other error is detected.
-In the event of an error, these functions set
+returns an error, or some other error is detected,
+\-1 is returned.
+.PP
+Both functions set
 .I errno
-to indicate the cause of the error.
+to an appropriate value in the case of an error.
 .SH ERRORS
 The
 .BR popen ()
-- 
2.4.11


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Re: [PATCH] popen.3: RETURN VALUE: describe successful case

[Michael Kerrisk (man-pages)]

On 04/28/2016 04:54 PM, Nikola Forró wrote:
> Reference:
> http://pubs.opengroup.org/onlinepubs/9699919799/functions/popen.html
> http://pubs.opengroup.org/onlinepubs/9699919799/functions/pclose.html

Thanks, Nikola. Patch applied.

Cheers,

Michael


> Signed-off-by: Nikola Forró <nforro-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  man3/popen.3 | 25 ++++++++++++++-----------
>  1 file changed, 14 insertions(+), 11 deletions(-)
> 
> diff --git a/man3/popen.3 b/man3/popen.3
> index f075581..bafa42c 100644
> --- a/man3/popen.3
> +++ b/man3/popen.3
> @@ -123,17 +123,18 @@ function waits for the associated process to terminate and returns the exit
>  status of the command as returned by
>  .BR wait4 (2).
>  .SH RETURN VALUE
> -The
> -.BR popen ()
> -function returns NULL if the
> +.BR popen ():
> +on success, returns a pointer to an open stream that
> +can be used to read or write to the pipe;
> +if the
>  .BR fork (2)
>  or
>  .BR pipe (2)
> -calls fail, or if it cannot allocate memory.
> -.PP
> -The
> -.BR pclose ()
> -function returns \-1 if
> +calls fail, or if the function cannot allocate memory,
> +NULL is returned.
> +
> +.BR pclose ():
> +on success, returns the exit status of the command; if
>  .\" These conditions actually give undefined results, so I commented
>  .\" them out.
>  .\" .I stream
> @@ -141,10 +142,12 @@ function returns \-1 if
>  .\".I stream
>  .\" already "pclose()d", or if
>  .BR wait4 (2)
> -returns an error, or some other error is detected.
> -In the event of an error, these functions set
> +returns an error, or some other error is detected,
> +\-1 is returned.
> +.PP
> +Both functions set
>  .I errno
> -to indicate the cause of the error.
> +to an appropriate value in the case of an error.
>  .SH ERRORS
>  The
>  .BR popen ()
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
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