XSI_SINGLE_PROCESS

XSI Single Process option group. More...

Files
file	time.h
	POSIX time-of-day types and functions (<sys/time.h>)

Macros
#define	F_LOCK   1
	Lock a region of a file (lockf command).
#define	F_TEST   3
	Test whether a file region is locked (lockf command).
#define	F_TLOCK   2
	Lock a region, failing immediately if blocked (lockf command).
#define	F_ULOCK   0
	Unlock a region (lockf command).

Functions
int	putenv (char *string)
	Add or change an environment variable (XSI extension).
struct tm *	getdate (const char *string)
	Convert a date-time string to broken-down time (XSI extension).
char *	strptime (const char *ZRESTRICT s, const char *ZRESTRICT format, struct tm *ZRESTRICT tm)
	Parse a date/time string according to a format (XSI extension).
int	mknod (const char *path, mode_t mode, dev_t dev)
	Create a special or regular file (XSI extension).
int	mknodat (int fd, const char *path, mode_t mode, dev_t dev)
	Create a special or regular file relative to a directory descriptor (XSI).
int	gettimeofday (struct timeval *tv, void *tz)
	Get the current time with microsecond resolution.
char *	crypt (const char *key, const char *salt)
	Encrypt a password string (XSI extension, not recommended for new code).
void	encrypt (char block[64], int edflag)
	Encrypt or decrypt a 64-bit block using DES (XSI extension).
long	gethostid (void)
	Get a unique identifier for the host system (XSI extension).
int	lockf (int fildes, int function, off_t size)
	Apply, test, or remove an advisory file lock (XSI extension).
int	setregid (gid_t rgid, gid_t egid)
	Set the real and effective group IDs (XSI extension).
int	setreuid (uid_t ruid, uid_t euid)
	Set the real and effective user IDs (XSI extension).
void	swab (const void *ZRESTRICT src, void *ZRESTRICT dest, ssize_t nbytes)
	Swap bytes in a block of memory (XSI extension).
void	sync (void)
	Schedule outstanding writes to all file systems (XSI extension).

Variables
int	daylight
	Non-zero if Daylight Saving Time is in effect.
long	timezone
	Offset in seconds from UTC for the current timezone.

Detailed Description

XSI Single Process option group.

Covers gethostid(), crypt(), encrypt(), setregid(), setreuid(), nice(), sync(), swab(), lockf(), and other XSI-mandatory single-process functions.

Macro Definition Documentation

F_LOCK

#define F_LOCK   1

Lock a region of a file (lockf command).

Definition at line 91 of file unistd.h.

F_TEST

#define F_TEST   3

Test whether a file region is locked (lockf command).

Definition at line 93 of file unistd.h.

F_TLOCK

#define F_TLOCK   2

Lock a region, failing immediately if blocked (lockf command).

Definition at line 95 of file unistd.h.

F_ULOCK

#define F_ULOCK   0

Unlock a region (lockf command).

Definition at line 97 of file unistd.h.

Function Documentation

crypt()

char * crypt	(	const char *	key,
		const char *	salt
	)

Encrypt a password string (XSI extension, not recommended for new code).

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/crypt.html

encrypt()

void encrypt	(	char	block[64],
		int	edflag
	)

Encrypt or decrypt a 64-bit block using DES (XSI extension).

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/encrypt.html

getdate()

struct tm * getdate

(

const char *

string

)

Convert a date-time string to broken-down time (XSI extension).

Parameters

string

Date-time string; the format is determined by the DATEMSK environment variable.

Returns

Pointer to a broken-down time, or NULL on failure.

gethostid()

long gethostid

(

void

)

Get a unique identifier for the host system (XSI extension).

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/gethostid.html

gettimeofday()

int gettimeofday	(	struct timeval *	tv,
		void *	tz
	)

Get the current time with microsecond resolution.

Parameters

tv	Output: current time; tv_sec is seconds and tv_usec is microseconds since the Epoch.
tz	Deprecated, must be NULL.

Returns

0 on success, or -1 with errno set on failure.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/gettimeofday.html

lockf()

int lockf	(	int	fildes,
		int	function,
		off_t	size
	)

Apply, test, or remove an advisory file lock (XSI extension).

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/lockf.html

mknod()

int mknod	(	const char *	path,
		mode_t	mode,
		dev_t	dev
	)

Create a special or regular file (XSI extension).

mknodat()

int mknodat	(	int	fd,
		const char *	path,
		mode_t	mode,
		dev_t	dev
	)

Create a special or regular file relative to a directory descriptor (XSI).

putenv()

int putenv

(

char *

string

)

Add or change an environment variable (XSI extension).

string must be of the form "NAME=value". The string is placed directly in the environment, so it must remain valid for the lifetime of the process.

Parameters

string

Environment entry of the form "NAME=value".

Returns

0 on success, or -1 with errno set on failure.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/putenv.html

setregid()

int setregid	(	gid_t	rgid,
		gid_t	egid
	)

Set the real and effective group IDs (XSI extension).

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/setregid.html

setreuid()

int setreuid	(	uid_t	ruid,
		uid_t	euid
	)

Set the real and effective user IDs (XSI extension).

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/setreuid.html

strptime()

char * strptime	(	const char *ZRESTRICT	s,
		const char *ZRESTRICT	format,
		struct tm *ZRESTRICT	tm
	)

Parse a date/time string according to a format (XSI extension).

Parameters

s	Input string to parse.
format	Format string describing the date/time fields to parse.
tm	Output: filled-in broken-down time structure.

Returns

Pointer to the first character in s not consumed by parsing, or NULL on failure.

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/strptime.html

swab()

void swab	(	const void *ZRESTRICT	src,
		void *ZRESTRICT	dest,
		ssize_t	nbytes
	)

Swap bytes in a block of memory (XSI extension).

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/swab.html

sync()

void sync

(

void

)

Schedule outstanding writes to all file systems (XSI extension).

See also

https://pubs.opengroup.org/onlinepubs/9699919799/functions/sync.html

Variable Documentation

daylight

int daylight

extern

Non-zero if Daylight Saving Time is in effect.

timezone

long timezone

extern

Offset in seconds from UTC for the current timezone.