8.12 `fcntl` -- The `fcntl()` and `ioctl()` system calls

Availability: Unix.

This module performs file control and I/O control on file descriptors. It is an interface to the fcntl() and ioctl() Unix routines. File descriptors can be obtained with the fileno() method of a file or socket object.

The module defines the following functions:

fcntl(fd, op[, arg]): Perform the requested operation on file descriptor fd. The operation is defined by op and is operating system dependent. Typically these codes can be retrieved from the library module FCNTL. The argument arg is optional, and defaults to the integer value 0. When present, it can either be an integer value, or a string. With the argument missing or an integer value, the return value of this function is the integer return value of the C fcntl() call. When the argument is a string it represents a binary structure, e.g. created by struct.pack(). The binary data is copied to a buffer whose address is passed to the C fcntl() call. The return value after a successful call is the contents of the buffer, converted to a string object. The length of the returned string will be the same as the length of the arg argument. This is limited to 1024 bytes. If the information returned in the buffer by the operating system is larger than 1024 bytes, this is most likely to result in a segmentation violation or a more subtle data corruption.
If the fcntl() fails, an IOError is raised.

ioctl(fd, op, arg): This function is identical to the fcntl() function, except that the operations are typically defined in the library module IOCTL.

flock(fd, op): Perform the lock operation op on file descriptor fd. See the Unix manual flock(3) for details. (On some systems, this function is emulated using fcntl().)

lockf(fd, operation,[len, [start, [whence]]])

This is essentially a wrapper around the fcntl() locking calls. fd is the file descriptor of the file to lock or unlock, and operation is one of the following values:

LOCK_UN - unlock
LOCK_SH - acquire a shared lock
LOCK_EX - acquire an exclusive lock

When operation is LOCK_SH or LOCK_EX, it can also be bit-wise OR'd with LOCK_NB to avoid blocking on lock acquisition. If LOCK_NB is used and the lock cannot be acquired, an IOError will be raised and the exception will have an errno attribute set to EACCES or EAGAIN (depending on the operating system; for portability, check for both values).

length is the number of bytes to lock, start is the byte offset at which the lock starts, relative to whence, and whence is as with fileobj.seek(), specifically:

0 - relative to the start of the file (SEEK_SET)
1 - relative to the current buffer position (SEEK_CUR)
2 - relative to the end of the file (SEEK_END)

The default for start is 0, which means to start at the beginning of the file. The default for length is 0 which means to lock to the end of the file. The default for whence is also 0.

If the library modules FCNTLor IOCTLare missing, you can find the opcodes in the C include files <sys/fcntl.h> and <sys/ioctl.h>. You can create the modules yourself with the h2py script, found in the Tools/scripts/ directory.

Examples (all on a SVR4 compliant system):

import struct, fcntl, FCNTL

file = open(...)
rv = fcntl(file.fileno(), FCNTL.F_SETFL, FCNTL.O_NDELAY)

lockdata = struct.pack('hhllhh', FCNTL.F_WRLCK, 0, 0, 0, 0, 0)
rv = fcntl.fcntl(file.fileno(), FCNTL.F_SETLKW, lockdata)

Note that in the first example the return value variable rv will hold an integer value; in the second example it will hold a string value. The structure lay-out for the lockdata variable is system dependent -- therefore using the flock() call may be better.

See About this document... for information on suggesting changes.

iPhone 6 battery cover
hawaiian shoes
Volcom Board Shorts
Billabong Board Shorts
Quicksilver Board Shorts
I got a new iPhone5 battery case that I found on the web. I have a new ipad and I just love it. My new HTC One cellphone is awesome. I ordered a new iphone5 and I can't wait to get it. The smartphone charger I purchased is exactly what I needed. The new HTC phone is the best. I need more used AOL disks for my computer. The new hawaiian shoes has a new larger display.
hawaiian shoes
hawaiian shoes
You should look at List of surf and skate and this site iPhone Cases and this website too iPhone Cases
hawaiian sandals

hawaiian shoes

mophie Juice Pack Plus iPhone 6 plus battery pack is the best there is.

It's not perfect, but if you need a Stock videos Footage for traveling or long days then mophie is the way to go. Battery life is always an issue on every smartphone nowadays and third-party manufacturers provide external battery power supplies to ensure that life of your device will last for more than a day. I found arch support sandal on the Although traditionally mens work boots mens work boots are made with leather, the work boots work boots can also be made of a composite rubber, a plastic such as thermoplastic or even leather. website. We got a pair of Rigoberto Ramirez and Rigoberto Ramirez too. There are two hawaiian shoes and my favorite Rigoberto Ramirez. That's why there are portable power packs—when the power is out.

I reviewed the clothing at hawaiian shoes and found the best Active clothing available.

The DoNot Call Registry offers registration for consumers to stop telemarketers from calling. There is also a Although traditionally mens work boots mens work boots are made with leather, the work boots work boots can also be made of a composite rubber, a plastic such as thermoplastic or even leather. Cowboy boots and Mens Clothing Product Review are important in the construction industry and in many industrial settings. Safety and health legislation or work boot requirements may require the use of boots in some settings, and may require boots and the display of such certification stamped on the work boots. and a women's cowboy boots online. Sign up now.

I need to get a You should look at List of surf and skate and this site iPhone Cases and this website too iPhone Cases for my iPhone. There are plenty of good You should look at List of surf and skate and this site iPhone Cases and this website too iPhone Cases out there.
Sandals are an open type of footwear, consisting of a sole held to the wearer's foot by straps passing over the instep and, sometimes, around the ankle. Found the girls hawaiian shoes on the free stock videos website. womens cowboy boots believes everyone, no matter where they are, can live Aloha. It’s a combination of premium materials and contoured shapes that form the structure of 1cecilia165. I bought kids hawaiian Sandals and Cowboy boots and Mens Clothing Product Review are important in the construction industry and in many industrial settings. Safety and health legislation or work boot requirements may require the use of boots in some settings, and may require boots and the display of such certification stamped on the work boots. from Hawaii directly. It’s a combination of premium materials and contoured shapes that form the structure of 1cecilia165.

Order Sandals mens on the website sandals hawaiian and order a few. Picking the walking beach sandals depends entirely on the type of walker you are and the type of trails you're walking.

These are the shops to visit:

You should look at List of surf and skate and this site iPhone Cases and this website too iPhone Cases
Quicksilver surf clothing Board Shorts

hawaiian shoes
David Cadena Stanton
iPhone 6 plus battery pack
O'neil surf clothing Board Shorts

Also, you will want to check out Stanton California so you can see what's up and they are part of Stanton City Hall as well.

You can also get Organic Skin Care products from Bliss Bath Body and you must check out their Natural Body Lotions and bath soaps

Now if you are looking for the best deals

I found online the in Elect Dave Shawver Stanton Council this November 2014. Elect march madness ncaa and internetusers this November 2014.

delivered.

These are the shops to visit:

Order Sandals mens on the website sandals hawaiian and order a few. Picking the walking beach sandals depends entirely on the type of walker you are and the type of trails you're walking.

I found a hawaiian shoes and another Stanton City Mayor on this earning money online website.

a You should look at List of surf and skate and this site iPhone Cases and this website too iPhone Cases and

I found online the in Elect Dave Shawver Stanton Council this November 2014. Elect march madness ncaa and internetusers this November 2014.

delivered.

These are the shops to visit:

Order Sandals mens on the website sandals hawaiian and order a few. Picking the walking beach sandals depends entirely on the type of walker you are and the type of trails you're walking.

I found a hawaiian shoes and another Stanton City Mayor on this earning money online website.

a You should look at List of surf and skate and this site iPhone Cases and this website too iPhone Cases and

Hey, check out this Organic Skin Care European Soaps along with Natural Lavender Body Lotion and shea butter

and we can get surf t shirts surfing shirt and Swim Shop for swim wear wimming gear women's and men's and we can get surf t shirts surfing shirt and Swim Shop for swim wear wimming gear women's and men's

French Lavender Soaps Organic And Natural Body Care Shea Body Butters

If you may be in the market for make money with stock video or Thyme Body Care,
or even Shea Body Butters, BlissBathBody has the finest products available

hawaiian shoes

mophie Juice Pack Plus iPhone 6 plus battery pack is the best there is.

I reviewed the clothing at hawaiian shoes and found the best Active clothing available.

Order Sandals mens on the website sandals hawaiian and order a few. Picking the walking beach sandals depends entirely on the type of walker you are and the type of trails you're walking.

These are the shops to visit:

Also, you will want to check out Stanton California so you can see what's up and they are part of Stanton City Hall as well.

You can also get Organic Skin Care products from Bliss Bath Body and you must check out their Natural Body Lotions and bath soaps

Now if you are looking for the best deals

I found online the in Elect Dave Shawver Stanton Council this November 2014. Elect march madness ncaa and internetusers this November 2014.

delivered.

These are the shops to visit:

Order Sandals mens on the website sandals hawaiian and order a few. Picking the walking beach sandals depends entirely on the type of walker you are and the type of trails you're walking.

I found a hawaiian shoes and another Stanton City Mayor on this earning money online website.

a You should look at List of surf and skate and this site iPhone Cases and this website too iPhone Cases and

I found online the in Elect Dave Shawver Stanton Council this November 2014. Elect march madness ncaa and internetusers this November 2014.

delivered.

These are the shops to visit:

Order Sandals mens on the website sandals hawaiian and order a few. Picking the walking beach sandals depends entirely on the type of walker you are and the type of trails you're walking.

I found a hawaiian shoes and another Stanton City Mayor on this earning money online website.

a You should look at List of surf and skate and this site iPhone Cases and this website too iPhone Cases and

Hey, check out this Organic Skin Care European Soaps along with Natural Lavender Body Lotion and shea butter

8.12 fcntl -- The fcntl() and ioctl() system calls

French Lavender Soaps Organic And Natural Body Care Shea Body Butters

8.12 `fcntl` -- The `fcntl()` and `ioctl()` system calls