get_phys_pages.3 review

get_phys_pages.3 review

[William Woodruff]

Hello all,

I've drafted a man page for two glib functions that haven't been
documented by the man-pages project yet: get_phys_pages(3) and
get_avphys_pages(3).

This is my first whole file contribution, so I was hoping I could
get some suggestions/pointers before submitting the actual patch :).

I based it largely on get_nprocs(3) manual page.

Copied below:

.\" Copyright (c) 2015 William Woodruff (william-d4iiUcZhRQBWk0Htik3J/w@public.gmane.org)
.\"
.\" %%%LICENSE_START(VERBATIM)
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\" %%%LICENSE_END
.\"
.TH GET_PHYS_PAGES 3  2015-03-02 "GNU" "Linux Programmer's Manual"
.SH NAME
get_phys_pages, get_avphys_pages \- get total and available physical
page counts
.SH SYNOPSIS
.nf
.B "#include <sys/sysinfo.h>"
.sp
.B long int get_phys_pages(void);
.B long int get_av_phys_pages(void);
.SH DESCRIPTION
The function
.BR get_phys_pages ()
returns the total number of physical pages of memory available on the
system.
.sp
The function
.BR get_avphys_pages ()
returns the number of available physical pages of memory available on the
system.
.SH RETURN VALUE
As given in DESCRIPTION.
.SH CONFORMING TO
These functions are GNU extensions.
.SH NOTES
The following
.BR sysconf (3)
calls make use of the functions documented on this page to return the same
information.
.sp
.nf
    total_pages = sysconf(_SC_PHYS_PAGES);    /* total pages of memory */
    avl_pages = sysconf(_SC_AVPHYS_PAGES);    /* available pages of memory*/
.fi
.SH EXAMPLE
The following example shows how
.BR get_phys_pages ()
and
.BR get_avphys_pages ()
can be used.
.sp
.nf
#include <stdio.h>
#include <sys/sysinfo.h>

int
main(int argc, char *argv[])
{
    printf("This system has %ld pages of physical memory and "
            "%ld pages of physical memory available.\\n",
            get_phys_pages(), get_avphys_pages());
    return 0;
}
.fi


---
William Woodruff
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Re: get_phys_pages.3 review

[Michael Kerrisk (man-pages)]

Hello William,

On 05/03/2015 11:06 PM, William Woodruff wrote:
> Hello all,
> 
> I've drafted a man page for two glib functions that haven't been
> documented by the man-pages project yet: get_phys_pages(3) and
> get_avphys_pages(3).
> 
> This is my first whole file contribution, so I was hoping I could
> get some suggestions/pointers before submitting the actual patch :).
> 
> I based it largely on get_nprocs(3) manual page.

Thanks for tackling this. Some comments below.

> Copied below:
> 
> .\" Copyright (c) 2015 William Woodruff (william-d4iiUcZhRQBWk0Htik3J/w@public.gmane.org)
> .\"
> .\" %%%LICENSE_START(VERBATIM)
> .\" Permission is granted to make and distribute verbatim copies of this
> .\" manual provided the copyright notice and this permission notice are
> .\" preserved on all copies.
> .\"
> .\" Permission is granted to copy and distribute modified versions of this
> .\" manual under the conditions for verbatim copying, provided that the
> .\" entire resulting derived work is distributed under the terms of a
> .\" permission notice identical to this one.
> .\"
> .\" Since the Linux kernel and libraries are constantly changing, this
> .\" manual page may be incorrect or out-of-date.  The author(s) assume no
> .\" responsibility for errors or omissions, or for damages resulting from
> .\" the use of the information contained herein.  The author(s) may not
> .\" have taken the same level of care in the production of this manual,
> .\" which is licensed free of charge, as they might when working
> .\" professionally.
> .\"
> .\" Formatted or processed versions of this manual, if unaccompanied by
> .\" the source, must acknowledge the copyright and authors of this work.
> .\" %%%LICENSE_END
> .\"
> .TH GET_PHYS_PAGES 3  2015-03-02 "GNU" "Linux Programmer's Manual"
> .SH NAME
> get_phys_pages, get_avphys_pages \- get total and available physical
> page counts
> .SH SYNOPSIS
> .nf
> .B "#include <sys/sysinfo.h>"
> .sp
> .B long int get_phys_pages(void);
> .B long int get_av_phys_pages(void);
> .SH DESCRIPTION
> The function
> .BR get_phys_pages ()
> returns the total number of physical pages of memory available on the
> system.
> .sp

No need for .sp here. Just use a blank line for the para break.

> The function
> .BR get_avphys_pages ()
> returns the number of available physical pages of memory available on the
> system.
> .SH RETURN VALUE
> As given in DESCRIPTION.

Change this to:

[[
On success, these functions return a nonnegative value
as given in DESCRIPTION.
On failure, they return \-1 and set
.I errno
to indicate the cause of the error.
]]

Taking a look at the glibc source reveals the following possible
errno value:

[[
.SH ERRORS
.TP
.B ENOSYS
The system could not provide the required information
(possibly because the
.I /proc
filesystem was not mounted).
]]

> .SH CONFORMING TO
> These functions are GNU extensions.
> .SH NOTES

I think it might also be useful to note some details about the
implementation here, since it relies on /proc, which may not
be available in some unusual configurations. How about this
paragraph, to give the reader a clue:

[[
These functions obtain the required information by scanning the
.I MemTotal
and
.I MemFree
fields of the file
.IR /proc/meminfo .
]]

> The following
> .BR sysconf (3)
> calls make use of the functions documented on this page to return the same
> information.

It's good that you add this piece, but I think the above text could be
recast to give the reader an important hint:

[[
The following
.BR sysconf (3)
provide a portable means of obtaining the same information
as the functions described on this page.
]]

> .sp

Use a blank line here, not ".sp"

> .nf
>     total_pages = sysconf(_SC_PHYS_PAGES);    /* total pages of memory */
>     avl_pages = sysconf(_SC_AVPHYS_PAGES);    /* available pages of memory*/
> .fi

The two code lines above render wider than 80 characters. Best to
shorten the comments by removing the "of memory" in both lines.

> .SH EXAMPLE
> The following example shows how
> .BR get_phys_pages ()
> and
> .BR get_avphys_pages ()
> can be used.
> .sp
> .nf
> #include <stdio.h>
> #include <sys/sysinfo.h>
> 
> int
> main(int argc, char *argv[])
> {
>     printf("This system has %ld pages of physical memory and "
>             "%ld pages of physical memory available.\\n",
>             get_phys_pages(), get_avphys_pages());
>     return 0;

I prefer

    exit(EXIT_SUCCESS);

here, in which case you'll also need to include <stdlib.h>.

> }
> .fi

Add:

[[
.SH SEE ALSO
.BR sysconf (3)
]]

Cheers,

Michael


-- 
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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Re: get_phys_pages.3 review

[J William Piggott]

On 05/04/2015 04:08 AM, Michael Kerrisk (man-pages) wrote:
> Hello William,
> 
> On 05/03/2015 11:06 PM, William Woodruff wrote:


>> returns the total number of physical pages of memory available on the
>> system.
>> .sp
> 
> No need for .sp here. Just use a blank line for the para break.

This is Groff specific behavior. From roff(7):
 ·      Never include empty or blank lines in a roff document.

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Re: get_phys_pages.3 review

[Michael Kerrisk (man-pages)]

Hi William,

On 05/04/2015 02:58 PM, J William Piggott wrote:
> On 05/04/2015 04:08 AM, Michael Kerrisk (man-pages) wrote:
>> Hello William,
>>
>> On 05/03/2015 11:06 PM, William Woodruff wrote:
> 
> 
>>> returns the total number of physical pages of memory available on the
>>> system.
>>> .sp
>>
>> No need for .sp here. Just use a blank line for the para break.
> 
> This is Groff specific behavior. From roff(7):
>  ·      Never include empty or blank lines in a roff document.

I'm not sure whether that text applies or not. But in any case,
we've got hundreds of pages that happily use blank lines.
If you mist, you can instead use ".PP", but ".sp" seems
wrong to me.

Thanks,

Michael

-- 
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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Re: get_phys_pages.3 review

[William Woodruff]

Hi Michael, William,

On 05/04/2015 09:52 AM, Michael Kerrisk (man-pages) wrote:
> Hi William,
> 
> On 05/04/2015 02:58 PM, J William Piggott wrote:
>> On 05/04/2015 04:08 AM, Michael Kerrisk (man-pages) wrote:
>>> Hello William,
>>>
>>> On 05/03/2015 11:06 PM, William Woodruff wrote:
>>
>>
>>>> returns the total number of physical pages of memory available on the
>>>> system.
>>>> .sp
>>>
>>> No need for .sp here. Just use a blank line for the para break.
>>
>> This is Groff specific behavior. From roff(7):
>>  ·      Never include empty or blank lines in a roff document.
> 
> I'm not sure whether that text applies or not. But in any case,
> we've got hundreds of pages that happily use blank lines.
> If you mist, you can instead use ".PP", but ".sp" seems
> wrong to me.

I'll follow your advice here. I've seen the rule about never using
blank lines in groff, but if other pages do it, I'll assume the behavior
is reasonable.

Best,
William Woodruff

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Re: get_phys_pages.3 review

[William Woodruff]

Just following up on my previous message, here's the updated
page. If you think it's ready for addition, I'll submit the patch for
it tonight.

.\" Copyright (c) 2015 William Woodruff (william-d4iiUcZhRQBWk0Htik3J/w@public.gmane.org)
.\"
.\" %%%LICENSE_START(VERBATIM)
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\" %%%LICENSE_END
.\"
.TH GET_PHYS_PAGES 3  2015-03-02 "GNU" "Linux Programmer's Manual"
.SH NAME
get_phys_pages, get_avphys_pages \- get total and available physical
page counts
.SH SYNOPSIS
.nf
.B "#include <sys/sysinfo.h>"
.sp
.B long int get_phys_pages(void);
.B long int get_av_phys_pages(void);
.SH DESCRIPTION
The function
.BR get_phys_pages ()
returns the total number of physical pages of memory available on the
system.

The function
.BR get_avphys_pages ()
returns the number of available physical pages of memory available on the
system.
.SH RETURN VALUE
On success, these functions return a nonnegative value as given in
DESCRIPTION.
On failure, they return \-1 and set
.I errno
to indicate the cause of the error.
.SH ERRORS
.TP
.B ENOSYS
The system could not provide the required information
(possibly because the
.I /proc
filesystem was not mounted).
.SH CONFORMING TO
These functions are GNU extensions.
.SH NOTES
These functions obtain the required information by scanning the
.I MemTotal
and
.I MemFree
fields of
.IR /proc/meminfo .

The following
.BR sysconf (3)
calls provide a portable means of obtaining the same information as the
functions described on this page.

.nf
    total_pages = sysconf(_SC_PHYS_PAGES);    /* total pages */
    avl_pages = sysconf(_SC_AVPHYS_PAGES);    /* available pages */
.fi
.SH EXAMPLE
The following example shows how
.BR get_phys_pages ()
and
.BR get_avphys_pages ()
can be used.

.nf
#include <stdio.h>
#include <stdlib.h>
#include <sys/sysinfo.h>

int
main(int argc, char *argv[])
{
    printf("This system has %ld pages of physical memory and "
            "%ld pages of physical memory available.\\n",
            get_phys_pages(), get_avphys_pages());
    exit(EXIT_SUCCESS);
}
.fi
.SH SEE ALSO
.BR sysconf (3)


Best,
William

On 05/04/2015 09:58 AM, William Woodruff wrote:
> Hi Michael, William,
> 
> On 05/04/2015 09:52 AM, Michael Kerrisk (man-pages) wrote:
>> Hi William,
>>
>> On 05/04/2015 02:58 PM, J William Piggott wrote:
>>> On 05/04/2015 04:08 AM, Michael Kerrisk (man-pages) wrote:
>>>> Hello William,
>>>>
>>>> On 05/03/2015 11:06 PM, William Woodruff wrote:
>>>
>>>
>>>>> returns the total number of physical pages of memory available on the
>>>>> system.
>>>>> .sp
>>>>
>>>> No need for .sp here. Just use a blank line for the para break.
>>>
>>> This is Groff specific behavior. From roff(7):
>>>  ·      Never include empty or blank lines in a roff document.
>>
>> I'm not sure whether that text applies or not. But in any case,
>> we've got hundreds of pages that happily use blank lines.
>> If you mist, you can instead use ".PP", but ".sp" seems
>> wrong to me.
> 
> I'll follow your advice here. I've seen the rule about never using
> blank lines in groff, but if other pages do it, I'll assume the behavior
> is reasonable.
> 
> Best,
> William Woodruff
> 
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Re: get_phys_pages.3 review

[Michael Kerrisk (man-pages)]

Hi William,

On 05/04/2015 07:11 PM, William Woodruff wrote:
> Just following up on my previous message, here's the updated
> page. If you think it's ready for addition, I'll submit the patch for
> it tonight.

I think you can submit the page, but see one comment below.

> .\" Copyright (c) 2015 William Woodruff (william-d4iiUcZhRQBWk0Htik3J/w@public.gmane.org)
> .\"
> .\" %%%LICENSE_START(VERBATIM)
> .\" Permission is granted to make and distribute verbatim copies of this
> .\" manual provided the copyright notice and this permission notice are
> .\" preserved on all copies.
> .\"
> .\" Permission is granted to copy and distribute modified versions of this
> .\" manual under the conditions for verbatim copying, provided that the
> .\" entire resulting derived work is distributed under the terms of a
> .\" permission notice identical to this one.
> .\"
> .\" Since the Linux kernel and libraries are constantly changing, this
> .\" manual page may be incorrect or out-of-date.  The author(s) assume no
> .\" responsibility for errors or omissions, or for damages resulting from
> .\" the use of the information contained herein.  The author(s) may not
> .\" have taken the same level of care in the production of this manual,
> .\" which is licensed free of charge, as they might when working
> .\" professionally.
> .\"
> .\" Formatted or processed versions of this manual, if unaccompanied by
> .\" the source, must acknowledge the copyright and authors of this work.
> .\" %%%LICENSE_END
> .\"
> .TH GET_PHYS_PAGES 3  2015-03-02 "GNU" "Linux Programmer's Manual"
> .SH NAME
> get_phys_pages, get_avphys_pages \- get total and available physical
> page counts
> .SH SYNOPSIS
> .nf
> .B "#include <sys/sysinfo.h>"
> .sp
> .B long int get_phys_pages(void);
> .B long int get_av_phys_pages(void);
> .SH DESCRIPTION
> The function
> .BR get_phys_pages ()
> returns the total number of physical pages of memory available on the
> system.
> 
> The function
> .BR get_avphys_pages ()
> returns the number of available physical pages of memory available on the
> system.

One too many "available" in that last sentence.

Thanks,

Michael


> .SH RETURN VALUE
> On success, these functions return a nonnegative value as given in
> DESCRIPTION.
> On failure, they return \-1 and set
> .I errno
> to indicate the cause of the error.
> .SH ERRORS
> .TP
> .B ENOSYS
> The system could not provide the required information
> (possibly because the
> .I /proc
> filesystem was not mounted).
> .SH CONFORMING TO
> These functions are GNU extensions.
> .SH NOTES
> These functions obtain the required information by scanning the
> .I MemTotal
> and
> .I MemFree
> fields of
> .IR /proc/meminfo .
> 
> The following
> .BR sysconf (3)
> calls provide a portable means of obtaining the same information as the
> functions described on this page.
> 
> .nf
>     total_pages = sysconf(_SC_PHYS_PAGES);    /* total pages */
>     avl_pages = sysconf(_SC_AVPHYS_PAGES);    /* available pages */
> .fi
> .SH EXAMPLE
> The following example shows how
> .BR get_phys_pages ()
> and
> .BR get_avphys_pages ()
> can be used.
> 
> .nf
> #include <stdio.h>
> #include <stdlib.h>
> #include <sys/sysinfo.h>
> 
> int
> main(int argc, char *argv[])
> {
>     printf("This system has %ld pages of physical memory and "
>             "%ld pages of physical memory available.\\n",
>             get_phys_pages(), get_avphys_pages());
>     exit(EXIT_SUCCESS);
> }
> .fi
> .SH SEE ALSO
> .BR sysconf (3)
> 
> 
> Best,
> William
> 
> On 05/04/2015 09:58 AM, William Woodruff wrote:
>> Hi Michael, William,
>>
>> On 05/04/2015 09:52 AM, Michael Kerrisk (man-pages) wrote:
>>> Hi William,
>>>
>>> On 05/04/2015 02:58 PM, J William Piggott wrote:
>>>> On 05/04/2015 04:08 AM, Michael Kerrisk (man-pages) wrote:
>>>>> Hello William,
>>>>>
>>>>> On 05/03/2015 11:06 PM, William Woodruff wrote:
>>>>
>>>>
>>>>>> returns the total number of physical pages of memory available on the
>>>>>> system.
>>>>>> .sp
>>>>>
>>>>> No need for .sp here. Just use a blank line for the para break.
>>>>
>>>> This is Groff specific behavior. From roff(7):
>>>>  ·      Never include empty or blank lines in a roff document.
>>>
>>> I'm not sure whether that text applies or not. But in any case,
>>> we've got hundreds of pages that happily use blank lines.
>>> If you mist, you can instead use ".PP", but ".sp" seems
>>> wrong to me.
>>
>> I'll follow your advice here. I've seen the rule about never using
>> blank lines in groff, but if other pages do it, I'll assume the behavior
>> is reasonable.
>>
>> Best,
>> William Woodruff
>>
> 


-- 
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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