.I cap_user_*_t

types) is subject to extension with each kernel revision,

but old programs will keep working.

The portable interfaces are

.BR cap_set_proc (3)

and

.I struct timeval

(as specified in

.IR <sys/time.h> ):

.in +4n

.EX

struct timeval {

};

.EE

.in

and gives the number of seconds and microseconds since the Epoch (see

.BR time (2)).

The

.I tz

argument is a

.IR "struct timezone" :

.in +4n

.EX

struct timezone {

.I timespec

is used to specify intervals of time with nanosecond precision.

It is defined as follows:

.in +4n

.nf

struct timespec {

.I buf1

and the second 10 bytes into

.IR buf2 .

.nf

#include <sys/uio.h>

.BR preadv (),

.BR pwritev ():

nonstandard, but present also on the modern BSDs.

.BR preadv2 (),

.BR pwritev2 ():

nonstandard Linux extension.

.BR proc (5),

.BR signal (7),

.BR socket (7)

Various pages from the

.I libseccomp

library, including:

.BR seccomp_rule_add (3),

and

.BR seccomp_export_bpf (3).

The kernel source files

.IR Documentation/networking/filter.txt

and

.IR Documentation/prctl/seccomp_filter.txt .

McCanne, S. and Jacobson, V. (1992)

.IR "The BSD Packet Filter: A New Architecture for User-level Packet Capture" ,

Proceedings of the USENIX Winter 1993 Conference

The elements of this structure are of type

.IR "struct sembuf" ,

containing the following members:

.in +4n

.nf

unsigned short sem_num; /* semaphore number */

The

.I sigaction

structure is defined as something like:

.in +4n

.nf

struct sigaction {

The

.I siginfo_t

data type is a structure with the following fields:

.in +4n

.nf

siginfo_t {

and kernel scheduling delays mean that the interval

may overrun by a small amount.)

This argument is of the following type:

.in +4n

.nf

struct timespec {

}

.fi

.in

If both fields of this structure are specified as 0, a poll is performed:

.BR sigtimedwait ()

returns immediately, either with information about a signal that

.I <db.h>

include file, and contains at

least the following fields:

.in +4n

.nf

typedef struct {

This information is returned in a

.I Dl_info

structure:

.in +4n

.nf

typedef struct {

is defined in

.I <net/ethernet.h>

as:

.in +4n

.nf

struct ether_addr {

.EX

.BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */"

.B "#include <fenv.h>"

.BI "int feenableexcept(int " excepts );

.BI "int fedisableexcept(int " excepts );

.B "int fegetexcept(void);"

.BR group (5)).

.PP

The \fIgroup\fP structure is defined in \fI<grp.h>\fP as follows:

.in +4n

.nf

struct group {

.BR passwd (5)).

.PP

The \fIpasswd\fP structure is defined in \fI<pwd.h>\fP as follows:

.in +4n

.nf

struct passwd {

SVr4, 4.3BSD, C89.

.SH EXAMPLE

The program below produces results such as the following:

.nf

.in +4n

.RB "$" " ./a.out 2560"

The time is returned in

.IR tp ,

which is declared as follows:

.in +4n

.nf

struct timeb {

In 4.3BSD the name was changed to

.BR lgamma (3),

and the man page promises

.in +4n

"At some time in the future the name gamma will be rehabilitated

and used for the Gamma function"

.in

This did indeed happen in 4.4BSD, where

.BR gamma ()

computes the Gamma function (with no effect on

structure used by

.BR getaddrinfo ()

contains the following fields:

.in +4n

.nf

struct addrinfo {

Each request is described by a

.I gaicb

structure, defined as follows:

.in +4n

.nf

struct gaicb {

The \fIgroup\fP structure is defined in

.I <grp.h>

as follows:

.in +4n

.nf

struct group {

the POSIX version of functions like

.BR getpwnam_r (3).

Other systems use the prototype

.in +4n

.nf

struct group *getgrent_r(struct group *grp, char *buf,

int buflen);

.fi

.in

or, better,

.in +4n

.nf

int getgrent_r(struct group *grp, char *buf, int buflen,

.IR gid .

.PP

The \fIgroup\fP structure is defined in \fI<grp.h>\fP as follows:

.in +4n

.nf

struct group {

.PP

.PP

The \fIhostent\fP structure is defined in \fI<netdb.h>\fP as follows:

.in +4n

.nf

struct hostent {

The list consists of

.I ifaddrs

structures, defined as follows:

.in +4n

.nf

struct ifaddrs {

functions return the names and addresses of a network host.

These functions return a pointer to the

following structure:

.in +4n

.nf

struct hostent {

structure is defined in

.I <mntent.h>

as follows:

.in +4n

.nf

struct mntent {

structure is defined in

.I <netdb.h>

as follows:

.in +4n

.nf

struct netent {

structure is defined in

.I <netdb.h>

as follows:

.in +4n

.nf

struct protoent {

.in

.PP

The \fIpasswd\fP structure is defined in \fI<pwd.h>\fP as follows:

.in +4n

.nf

struct passwd {

after all processing has been performed.

.PP

The \fIpasswd\fP structure is defined in \fI<pwd.h>\fP as follows:

.in +4n

.nf

struct passwd {

The \fIpasswd\fP structure is defined in

.I <pwd.h>

as follows:

.in +4n

.nf

struct passwd {

the POSIX version of functions like

.BR getpwnam_r (3).

Other systems use the prototype

.in +4n

.nf

struct passwd *

getpwent_r(struct passwd *pwd, char *buf, int buflen);

.fi

.in

or, better,

.nf

.in +4n

int

.IR uid .

.PP

The \fIpasswd\fP structure is defined in \fI<pwd.h>\fP as follows:

.in +4n

.nf

struct passwd {

structure is defined in

.I <netdb.h>

as follows:

.in +4n

.nf

struct servent {

.\" SUN doesn't have sgetspent_r()

.SS Structure

The shadow password structure is defined in \fI<shadow.h>\fP as follows:

.in +4n

.nf

struct spwd {

Feature Test Macro Requirements for glibc (see

.BR feature_test_macros (7)):

.in

.BR getutent_r (),

.BR getutid_r (),

.BR getutline_r ():

|| /* since glibc 2.19: */ _DEFAULT_SOURCE

|| /* glibc <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE

.fi

These functions are GNU extensions, analogs of the functions of the

same name without the _r suffix.

The

.IR errno .

.SH EXAMPLE

One example of use is the following code, which simulates typing

.in +4n

.EX

ls \-l *.c ../*.c

.EE

.in

in the shell:

.nf

.in +4n

The argument \fIitem\fP is of type \fIENTRY\fP, which is defined in

\fI<search.h>\fP as follows:

.in +4n

.nf

typedef struct entry {

char *key;

} ENTRY;

.in

.fi

The field \fIkey\fP points to a null-terminated string which is the

search key.

The field \fIdata\fP points to data that is associated with that key.

The

.I if_nameindex

structure contains at least the following entries:

.in +4n

.EX

unsigned int if_index; /* Index of interface (1, 2, ...) */

is defined in

.I <netinet/in.h>

as:

.in +4n

.EX

typedef uint32_t in_addr_t;

This value is an absolute timeout in seconds and nanoseconds

since the Epoch, 1970-01-01 00:00:00 +0000 (UTC),

specified in the following structure:

.in +4n

.nf

struct timespec {

into the

.IR stream .

The list of group members must be NULL-terminated or NULL-initialized.

The

.IR "struct group"

is defined as follows:

.in +4n

.EX

struct group {

structure \fIp\fP in the file associated with \fIstream\fP.

.PP

The \fIpasswd\fP structure is defined in \fI<pwd.h>\fP as follows:

.in +4n

.EX

struct passwd {

and

.BR srand (),

possibly useful when one needs the same sequence on two different machines.

.in +4n

.EX

static unsigned long next = 1;

.I value

argument is used to specify an accompanying item of data (either an integer

or a pointer value) to be sent with the signal, and has the following type:

.in +4n

.EX

union sigval {

.I n

characters are stored into

.IR str .

The terminating null character ('\\0') is written if and only if

.I n

is sufficiently large, otherwise the written string is truncated at

.I n

characters.

The

.BR strfromd (),

.BR strfromf (),

.BR g ,

or

.BR G .

The conversion specifier is applied based on the floating-point type

indicated by the function suffix.

Therefore, unlike

See

.BR snprintf (3)

for a detailed description of these conversion specifiers.

The implementation conforms to the C99 standard on conversion of NaN and

infinity values:

.PP

.BR E ,

.BR G )

is the conversion specifier, the conversion is to "NAN" or "-NAN".

Likewise if

.I fp

is infinity, it is converted to [-]inf or [-]INF.

and the

.B POSIX Safety Concepts

section in GNU C Library manual.

.TS

allbox;

lbw11 lb lb

.SH EXAMPLES

To convert the value 12.1 as a float type to a string using decimal

notation, resulting in "12.100000":

.in +4

.EX

#define __STDC_WANT_IEC_60559_BFP_EXT__

strfromf(s, ssize, "%f", 12.1);

.EE

.in

To convert the value 12.3456 as a float type to a string using

decimal notation with two digits of precision, resulting in "12.35":

.in +4

.EX

#define __STDC_WANT_IEC_60559_BFP_EXT__

strfromf(s, ssize, "%.2f", 12.3456);

.EE

.in

To convert the value 12.345e19 as a double type to a string using

scientific notation with zero digits of precision, resulting in "1E+20":

.in +4

.EX

#define __STDC_WANT_IEC_60559_BFP_EXT__

is defined in

.IR <time.h>

as follows:

.in +4n

.EX

struct tm {

.BR strptime ()

and

.BR strftime (3).

.EX

#define _XOPEN_SOURCE

#include <stdio.h>

implementation-defined numeric strings.

.LP

BSD also has

.in +4n

.EX

.BI "quad_t strtoq(const char *" nptr ", char **" endptr ", int " base );

Many of the functions described here have a \fItermios_p\fP argument

that is a pointer to a \fItermios\fP structure.

This structure contains at least the following members:

.in +4n

.EX

tcflag_t c_iflag; /* input modes */

structures, defined in

.I <sys/time.h>

as:

.in +4n

.EX

struct timeval {

LP_PSELECD unchanged selected input, active high

LP_PERRORP unchanged error input, active low

.TE

Refer to your printer manual for the meaning of the signals.

Note that undocumented bits may also be set, depending on your printer.

.IP "\fBint ioctl(int \fP\fIfd\fP\fB, LPRESET)\fP"

is supported.

.SS TIOCNOTTY

Detach the calling process from its controlling terminal.

If the process is the session leader,

then

.B SIGHUP

.B SIGCONT

signals are sent to the foreground process group

and all processes in the current session lose their controlling tty.

This

.BR ioctl (2)

call works only on file descriptors connected

Argument is an

.I ip_mreq_source

structure.

.in +4n

.EX

struct ip_mreq_source {

};

.EE

.in

The

.I ip_mreq_source

structure is similar to

Argument is an

.I ip_msfilter

structure.

.in +4n

.EX

struct ip_msfilter {

};

.EE

.in

There are two macros,

.BR MCAST_INCLUDE

and

};

.EE

.in

.I sin6_family

is always set to

.BR AF_INET6 ;

IFF_SLAVE_NEEDARP:Interface needs ARPs for validation.

IFF_ISATAP:Interface is RFC4214 ISATAP interface.

.TE

Setting the extended (private) interface flags is a privileged operation.

.TP

.BR SIOCGIFADDR ", " SIOCSIFADDR

macro in

.IR <net/if.h> .

Add the following to your program as a workaround:

.in +4n

.EX

#ifndef ifr_newname

Total Length:Always filled in

.TE

.RE

.PP

If

.B IP_HDRINCL

see below

T}:Interface Statistics.

.TE

The value type for

.B IFLA_STATS

is

.RE

.PP

See also

.UR http://physics.nist.gov\:/cuu\:/Units\:/binary.html

.UE

.SS Discussion

Use the given timezone as local time.

.B zic

will act as if the input contained a link line of the form

.ti +.5i

Link \fItimezone\fP localtime

.TP

timezone environment variables.

.B zic

will act as if the input contained a link line of the form

.ti +.5i

Link \fItimezone\fP posixrules

.TP

.nf

.ti +.5i

.ta \w'Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'TYPE\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u

Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S

For example:

.ti +.5i

Rule US 1967 1973 \- Apr lastSun 2:00 1:00 D

.fi

The fields that make up a rule line are:

.TP "\w'LETTER/S'u"

Recognized forms include:

.nf

.in +.5i

.ta \w'Sun<=25\0\0'u

5 the fifth of the month

lastSun the last Sunday in the month

Sun<=25 last Sunday on or before the 25th

.fi

.in -.5i

Names of days of the week may be abbreviated or spelled out in full.

Note that there must be no spaces within the

.B ON

Recognized forms include:

.nf

.in +.5i

.ta \w'1:28:13\0\0'u

2 time in hours

2:00 time in hours and minutes

\- equivalent to 0

.fi

.in -.5i

where hour 0 is midnight at the start of the day,

and hour 24 is midnight at the end of the day.

Any of these forms may be followed by the letter

the variable part is null.

.PP

A zone line has the form

.nf

.ti +.5i

.ta \w'Zone\0\0'u +\w'Australia/Adelaide\0\0'u +\w'UTCOFF\0\0'u +\w'RULES/SAVE\0\0'u +\w'FORMAT\0\0'u

Zone NAME UTCOFF RULES/SAVE FORMAT [UNTIL]

For example:

.ti +.5i

Zone Australia/Adelaide 9:30 Aus CST 1971 Oct 31 2:00

.fi

The fields that make up a zone line are:

.TP "\w'UTCOFF'u"

continuation.

.PP

A link line has the form

.nf

.ti +.5i

.ta \w'Link\0\0'u +\w'Europe/Istanbul\0\0'u

Link LINK-FROM LINK-TO

For example:

.ti +.5i

Link Europe/Istanbul Asia/Istanbul

.fi

The

.B LINK-FROM

.nf

.ti +.5i

.ta \w'Leap\0\0'u +\w'YEAR\0\0'u +\w'MONTH\0\0'u +\w'DAY\0\0'u +\w'HH:MM:SS\0\0'u +\w'CORR\0\0'u

Leap YEAR MONTH DAY HH:MM:SS CORR R/S

For example:

.ti +.5i

Leap 1974 Dec 31 23:59:60 + S

.fi

The

.BR YEAR ,