[RFC] if_nameindex.3: New page documenting if_nameindex(3) and if_freenameindex(3)

[RFC] if_nameindex.3: New page documenting if_nameindex(3) and if_freenameindex(3)

[YOSHIFUJI Hideaki]

Please review.
TODO: Check VERSIONS and HISTORY sections.

References:
	RFC 3542

	POSIX Man Page Set
		http://www.unix.com/man-page/POSIX/3posix/if_indexname
		http://www.unix.com/man-page/POSIX/3posix/if_freeindexname

	OS X Deverloper Tools Manual Page
		http://developer.apple.com/library/mac/#documentation/Darwin/Reference/Manpages/man3/if_nameindex.3.html

	Source: sysdeps/unix/sysv/linux/{if_index.c,ifaddrs.c}

YOSHIFUJI Hideaki <yoshfuji-VfPWfsRibaP+Ru+s062T9g@public.gmane.org>
---
 man3/if_nameindex.3 |  110 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 man3/if_nameindex.3

diff --git a/man3/if_nameindex.3 b/man3/if_nameindex.3
new file mode 100644
index 0000000..60bfd39
--- /dev/null
+++ b/man3/if_nameindex.3
@@ -0,0 +1,110 @@
+.\" Copyright (c) 2012 YOSHIFUJI Hideaki <yoshfuji-VfPWfsRibaP+Ru+s062T9g@public.gmane.org>
+.\" 
+.\" 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+.\" manual page may be incorrect or out-of-date.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.
+.\"
+.TH IF_NAMEINDEX 3 2012-11-16 "GNU" "Linux Programmer's Manual"
+.SH NAME
+if_nameindex, if_freenameindex \- get network interface names and indexes
+.SH SYNOPSIS
+.nf
+.B #include <net/if.h>
+.sp
+.BI "struct if_nameindex *if_nameindex(void);
+.BI "void if_freenameindex(struct if_nameindex *" "ptr" );
+.fi
+.SH DESCRIPTION
+The
+.BR if_nameindex ()
+function creates an array of structures, one structure per
+interface, each describing network interface name and
+corresponding network index of the local system.
+
+The
+.I if_nameindex
+structure contains at least the following entries:
+.sp
+.in +4n
+.nf
+    unsigned int if_index;  /* 1, 2, ... */
+    char *if_name;          /* null terminated name: "eth0", ... */
+.fi
+.in
+.PP
+The
+.I if_index
+field contains the interface index,
+or zero if this is the last item of the array.
+.PP
+The
+.I ifa_name
+field points to the null-terminated interface name,
+or NULL pointer if this is the last item of the array.
+.PP
+The data returned by
+.BR if_nameindex ()
+is dynamically allocated and should be freed using
+.BR if_freenameindex ()
+when no longer needed.
+.SH RETURN VALUE
+On success,
+.BR if_nameindex ()
+returns pointer to the array;
+on error, A NULL pointer is returned, and
+.I errno
+is set appropriately.
+.SH ERRORS
+.BR if_nameindex ()
+may fail and set
+.I errno
+if:
+.TP
+.B ENOBUFS
+Sufficient resources unavailable.
+.PP
+.BR if_nameindex ()
+may also fail for any of the errors specified for
+.BR socket (2),
+.BR bind (2),
+.BR ioctl (2),
+.BR getsockname (2),
+.BR recvmsg (2),
+.BR sendto (2),
+or
+.BR malloc (3).
+.SH VERSIONS
+The
+.BR if_nameindex ()
+function first appeared in glibc 2.3, but before glibc 2.3.3,
+the implementation only supported interfaces with IPv4 addresses.
+Support of interfaces without IPv4 addresses is only available
+on kernels that support netlink.
+.SH CONFORMING TO
+RFC\ 3493, POSIX.1-2001.
+.SH HISTORY
+This function first appeared in BSDi.
+.SH SEE ALSO
+.BR getsockopt (2),
+.BR setsockopt (2),
+.BR getifaddrs (3),
+.BR if_indextoname (3),
+.BR if_nameindex (3),
+.BR if_nametoindex (3),
+.BR ifconfig (8)
-- 
1.7.9.5

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Re: [RFC] if_nameindex.3: New page documenting if_nameindex(3) and if_freenameindex(3)

[Michael Kerrisk (man-pages)]

[-- Attachment #1: Type: text/plain, Size: 4363 bytes --]

On Fri, Nov 16, 2012 at 6:28 PM, YOSHIFUJI Hideaki
<yoshfuji-VfPWfsRibaP+Ru+s062T9g@public.gmane.org> wrote:
> Please review.

Thanks Hideaki.

I've merged this into a branch, made a number of fixes, and added an
example program. Could you check my changes in the diff below. (The
complete page is attached.)

Cheers,

Michael

diff --git a/man3/if_nameindex.3 b/man3/if_nameindex.3
index 60bfd39..23eaa5a 100644
--- a/man3/if_nameindex.3
+++ b/man3/if_nameindex.3
@@ -1,4 +1,5 @@
 .\" Copyright (c) 2012 YOSHIFUJI Hideaki <yoshfuji-VfPWfsRibaP+Ru+s062T9g@public.gmane.org>
+.\" and Copyright (c) 2012 Michael Kerrisk <mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
 .\"
 .\" Permission is granted to make and distribute verbatim copies of this
 .\" manual provided the copyright notice and this permission notice are
@@ -20,7 +21,7 @@
 .\" Formatted or processed versions of this manual, if unaccompanied by
 .\" the source, must acknowledge the copyright and authors of this work.
 .\"
-.TH IF_NAMEINDEX 3 2012-11-16 "GNU" "Linux Programmer's Manual"
+.TH IF_NAMEINDEX 3 2012-11-21 "GNU" "Linux Programmer's Manual"
 .SH NAME
 if_nameindex, if_freenameindex \- get network interface names and indexes
 .SH SYNOPSIS
@@ -33,32 +34,34 @@ if_nameindex, if_freenameindex \- get network
interface names and indexes
 .SH DESCRIPTION
 The
 .BR if_nameindex ()
-function creates an array of structures, one structure per
-interface, each describing network interface name and
-corresponding network index of the local system.
-
+function returns an array of
+.I if_nameindex
+structures, each containing information
+about one of the network interfaces on the local system.
 The
 .I if_nameindex
 structure contains at least the following entries:
 .sp
 .in +4n
 .nf
-    unsigned int if_index;  /* 1, 2, ... */
-    char *if_name;          /* null terminated name: "eth0", ... */
+    unsigned int if_index; /* Index of interface (1, 2, ...) */
+    char        *if_name;  /* Null-terminated name ("eth0", etc.) */
 .fi
 .in
 .PP
 The
 .I if_index
-field contains the interface index,
-or zero if this is the last item of the array.
-.PP
+field contains the interface index.
 The
 .I ifa_name
-field points to the null-terminated interface name,
-or NULL pointer if this is the last item of the array.
+field points to the null-terminated interface name.
+The end of the array is indicated by entry with
+.I if_index
+set to zero and
+.I ifa_name
+set to NULL.
 .PP
-The data returned by
+The data structure returned by
 .BR if_nameindex ()
 is dynamically allocated and should be freed using
 .BR if_freenameindex ()
@@ -67,7 +70,7 @@ when no longer needed.
 On success,
 .BR if_nameindex ()
 returns pointer to the array;
-on error, A NULL pointer is returned, and
+on error, a NULL pointer is returned, and
 .I errno
 is set appropriately.
 .SH ERRORS
@@ -77,7 +80,7 @@ may fail and set
 if:
 .TP
 .B ENOBUFS
-Sufficient resources unavailable.
+Insufficient resources unavailable.
 .PP
 .BR if_nameindex ()
 may also fail for any of the errors specified for
@@ -92,13 +95,51 @@ or
 .SH VERSIONS
 The
 .BR if_nameindex ()
-function first appeared in glibc 2.3, but before glibc 2.3.3,
+function first appeared in glibc 2.1, but before glibc 2.3.4,
 the implementation only supported interfaces with IPv4 addresses.
-Support of interfaces without IPv4 addresses is only available
+Support of interfaces that don't have IPv4 addresses is only available
 on kernels that support netlink.
+.SH EXAMPLE
+The program below demonstrates the use of the functions described
+on this page.
+An example of the output this program might produce is the following:
+.in +4n
+.nf
+$ \fB./a.out\fI
+1: lo
+2: wlan0
+3: em1
+.fi
+.in
+.SS Program source
+.nf
+#include <net/if.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+int
+main(int argc, char *argv[])
+{
+    struct if_nameindex *if_ni, *i;
+
+    if_ni = if_nameindex();
+    if (if_ni == NULL) {
+        perror("if_nameindex");
+        exit(EXIT_FAILURE);
+    }
+
+    for (i = if_ni; ! (i\->if_index == 0 && i\->if_name == NULL); i++)
+        printf("%d: %s\\n", i\->if_index, i\->if_name);
+
+    if_freenameindex(if_ni);
+
+    exit(EXIT_SUCCESS);
+}
+.fi
 .SH CONFORMING TO
 RFC\ 3493, POSIX.1-2001.
-.SH HISTORY
+
 This function first appeared in BSDi.
 .SH SEE ALSO
 .BR getsockopt (2),

[-- Attachment #2: if_nameindex.3 --]
[-- Type: application/octet-stream, Size: 3951 bytes --]

.\" Copyright (c) 2012 YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
.\" and Copyright (c) 2012 Michael Kerrisk <mtk.manpages@gmail.com>
.\" 
.\" 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.
.\"
.TH IF_NAMEINDEX 3 2012-11-21 "GNU" "Linux Programmer's Manual"
.SH NAME
if_nameindex, if_freenameindex \- get network interface names and indexes
.SH SYNOPSIS
.nf
.B #include <net/if.h>
.sp
.BI "struct if_nameindex *if_nameindex(void);
.BI "void if_freenameindex(struct if_nameindex *" "ptr" );
.fi
.SH DESCRIPTION
The
.BR if_nameindex ()
function returns an array of 
.I if_nameindex
structures, each containing information
about one of the network interfaces on the local system.
The
.I if_nameindex
structure contains at least the following entries:
.sp
.in +4n
.nf
    unsigned int if_index; /* Index of interface (1, 2, ...) */
    char        *if_name;  /* Null-terminated name ("eth0", etc.) */
.fi
.in
.PP
The
.I if_index
field contains the interface index.
The
.I ifa_name
field points to the null-terminated interface name.
The end of the array is indicated by entry with
.I if_index
set to zero and
.I ifa_name
set to NULL.
.PP
The data structure returned by
.BR if_nameindex ()
is dynamically allocated and should be freed using
.BR if_freenameindex ()
when no longer needed.
.SH RETURN VALUE
On success,
.BR if_nameindex ()
returns pointer to the array;
on error, a NULL pointer is returned, and
.I errno
is set appropriately.
.SH ERRORS
.BR if_nameindex ()
may fail and set
.I errno
if:
.TP
.B ENOBUFS
Insufficient resources unavailable.
.PP
.BR if_nameindex ()
may also fail for any of the errors specified for
.BR socket (2),
.BR bind (2),
.BR ioctl (2),
.BR getsockname (2),
.BR recvmsg (2),
.BR sendto (2),
or
.BR malloc (3).
.SH VERSIONS
The
.BR if_nameindex ()
function first appeared in glibc 2.1, but before glibc 2.3.4,
the implementation only supported interfaces with IPv4 addresses.
Support of interfaces that don't have IPv4 addresses is only available
on kernels that support netlink.
.SH EXAMPLE
The program below demonstrates the use of the functions described
on this page.
An example of the output this program might produce is the following:
.in +4n
.nf
$ \fB./a.out\fI
1: lo
2: wlan0
3: em1
.fi
.in
.SS Program source
.nf
#include <net/if.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

int
main(int argc, char *argv[])
{
    struct if_nameindex *if_ni, *i;

    if_ni = if_nameindex();
    if (if_ni == NULL) {
        perror("if_nameindex");
        exit(EXIT_FAILURE);
    }

    for (i = if_ni; ! (i\->if_index == 0 && i\->if_name == NULL); i++) 
        printf("%d: %s\\n", i\->if_index, i\->if_name);

    if_freenameindex(if_ni);

    exit(EXIT_SUCCESS);
} 
.fi
.SH CONFORMING TO
RFC\ 3493, POSIX.1-2001.

This function first appeared in BSDi.
.SH SEE ALSO
.BR getsockopt (2),
.BR setsockopt (2),
.BR getifaddrs (3),
.BR if_indextoname (3),
.BR if_nameindex (3),
.BR if_nametoindex (3),
.BR ifconfig (8)

Re: [RFC] if_nameindex.3: New page documenting if_nameindex(3) and if_freenameindex(3)

[YOSHIFUJI Hideaki]

Hi, Michael.

Michael Kerrisk (man-pages) wrote:
> On Fri, Nov 16, 2012 at 6:28 PM, YOSHIFUJI Hideaki
> <yoshfuji-VfPWfsRibaP+Ru+s062T9g@public.gmane.org> wrote:
>> Please review.
> 
> Thanks Hideaki.
> 
> I've merged this into a branch, made a number of fixes, and added an
> example program. Could you check my changes in the diff below. (The
> complete page is attached.)

> +    for (i = if_ni; ! (i\->if_index == 0 && i\->if_name == NULL); i++)
> +        printf("%d: %s\\n", i\->if_index, i\->if_name);

Since type of if_index is unsigned int, please use %u here.
Thanks.

--yoshfuji

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Re: [RFC] if_nameindex.3: New page documenting if_nameindex(3) and if_freenameindex(3)

[Michael Kerrisk (man-pages)]

On Thu, Nov 29, 2012 at 12:07 PM, YOSHIFUJI Hideaki
<yoshfuji-VfPWfsRibaP+Ru+s062T9g@public.gmane.org> wrote:
> Hi, Michael.
>
> Michael Kerrisk (man-pages) wrote:
>> On Fri, Nov 16, 2012 at 6:28 PM, YOSHIFUJI Hideaki
>> <yoshfuji-VfPWfsRibaP+Ru+s062T9g@public.gmane.org> wrote:
>>> Please review.
>>
>> Thanks Hideaki.
>>
>> I've merged this into a branch, made a number of fixes, and added an
>> example program. Could you check my changes in the diff below. (The
>> complete page is attached.)
>
>> +    for (i = if_ni; ! (i\->if_index == 0 && i\->if_name == NULL); i++)
>> +        printf("%d: %s\\n", i\->if_index, i\->if_name);
>
> Since type of if_index is unsigned int, please use %u here.
> Thanks.

Thanks. Fixed!

Cheers,

Michael

-- 
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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