Ref/shmop-Phpdoc专题
shmop_close
Close shared memory block
说明
void <span
class="methodname">shmop_close ( <span
class="type">Shmop $shmop )
shmop_close is used to close a shared memory block.
参数
shmop
The shared memory block resource created by <span
class="function">shmop_open
返回值
没有返回值。
更新日志
| 版本 | 说明 |
|---|---|
| 8.0.0 | shmop expects a Shmop instance now; previously, a resource was expected. |
范例
示例 #1 Closing shared memory block
<?php
shmop_close($shm_id);
?>This example will close shared memory block identified by $shm_id.
参见
- shmop_open
shmop_delete
Delete shared memory block
说明
bool <span
class="methodname">shmop_delete ( <span
class="methodparam">Shmop $shmop )
shmop_delete is used to delete a shared memory block.
参数
shmop
The shared memory block resource created by <span
class="function">shmop_open
返回值
成功时返回 true， 或者在失败时返回 false。
更新日志
| 版本 | 说明 |
|---|---|
| 8.0.0 | shmop expects a Shmop instance now; previously, a resource was expected. |
范例
示例 #1 Deleting shared memory block
<?php
shmop_delete($shm_id);
?>This example will delete shared memory block identified by $shm_id.
shmop_open
Create or open shared memory block
说明
Shmop<span
class="type">false <span
class="methodname">shmop_open ( <span
class="type">int $key , <span
class="type">string $mode , <span
class="methodparam">int $permissions
, int $size
)
shmop_open can create or open a shared memory block.
参数
key
System's id for the shared memory block. Can be passed as a decimal or
hex.
mode
The flags that you can use:
- "a" for access (sets SHM_RDONLY for shmat) use this flag when you need to open an existing shared memory segment for read only
- "c" for create (sets IPC_CREATE) use this flag when you need to create a new shared memory segment or if a segment with the same key exists, try to open it for read and write
- "w" for read & write access use this flag when you need to read and write to a shared memory segment, use this flag in most cases.
- "n" create a new memory segment (sets IPC_CREATE|IPC_EXCL) use this flag when you want to create a new shared memory segment but if one already exists with the same flag, fail. This is useful for security purposes, using this you can prevent race condition exploits.
permissions
The permissions that you wish to assign to your memory segment, those
are the same as permission for a file. Permissions need to be passed in
octal form, like for example 0644
size
The size of the shared memory block you wish to create in bytes
Note:
Note: the 3rd and 4th should be entered as 0 if you are opening an existing memory segment.
返回值
On success shmop_open will return a <span
class="classname">Shmop instance that you can use to access the
shared memory segment you've created. false is returned on
failure.
更新日志
| 版本 | 说明 |
|---|---|
| 8.0.0 | On success, this function returns an Shmop instance now; previously, a resource was returned. |
范例
示例 #1 Create a new shared memory block
<?php
$shm_key = ftok(__FILE__, 't');
$shm_id = shmop_open($shm_key, "c", 0644, 100);
?>This example opened a shared memory block with a system id returned by ftok.
参见
- shmop_close
- shmop_delete
shmop_read
Read data from shared memory block
说明
string <span
class="methodname">shmop_read ( <span
class="type">Shmop $shmop , <span
class="methodparam">int $offset ,
int $size )
shmop_read will read a string from shared memory block.
参数
shmop
The shared memory block identifier created by <span
class="function">shmop_open
offset
Offset from which to start reading
size
The number of bytes to read. 0 reads shmop_size($shmid) - $start
bytes.
返回值
Returns the data 或者在失败时返回 false.
更新日志
| 版本 | 说明 |
|---|---|
| 8.0.0 | shmop expects a Shmop instance now; previously, a resource was expected. |
范例
示例 #1 Reading shared memory block
<?php
$shm_data = shmop_read($shm_id, 0, 50);
?>This example will read 50 bytes from shared memory block and place the data inside $shm_data.
参见
- shmop_write
shmop_size
Get size of shared memory block
说明
int <span
class="methodname">shmop_size ( <span
class="type">Shmop $shmop )
shmop_size is used to get the size, in bytes of the shared memory block.
参数
shmop
The shared memory block identifier created by <span
class="function">shmop_open
返回值
Returns an int, which represents the number of bytes the shared memory block occupies.
更新日志
| 版本 | 说明 |
|---|---|
| 8.0.0 | shmop expects a Shmop instance now; previously, a resource was expected. |
范例
示例 #1 Getting the size of the shared memory block
<?php
$shm_size = shmop_size($shm_id);
?>This example will put the size of shared memory block identified by $shm_id into $shm_size.
shmop_write
Write data into shared memory block
说明
int <span
class="methodname">shmop_write ( <span
class="type">Shmop $shmop , <span
class="methodparam">string $data ,
int $offset
)
shmop_write will write a string into shared memory block.
参数
shmop
The shared memory block identifier created by <span
class="function">shmop_open
data
A string to write into shared memory block
offset
Specifies where to start writing data inside the shared memory segment.
返回值
The size of the written data.
更新日志
| 版本 | 说明 |
|---|---|
| 8.0.0 | Prior to PHP 8.0.0, false was returned on failure. |
| 8.0.0 | shmop expects a Shmop instance now; previously, a resource was expected. |
范例
示例 #1 Writing to shared memory block
<?php
$shm_bytes_written = shmop_write($shm_id, $my_string, 0);
?>This example will write data inside $my_string into shared memory block, $shm_bytes_written will contain the number of bytes written.
参见
- shmop_read
目录
- shmop_close — Close shared memory block
- shmop_delete — Delete shared memory block
- shmop_open — Create or open shared memory block
- shmop_read — Read data from shared memory block
- shmop_size — Get size of shared memory block
- shmop_write — Write data into shared memory block