How does PHP solve the problem of multiple processes reading and writing a file at the same time?

#How does PHP solve the problem of multiple processes reading and writing a file at the same time?

First of all, PHP supports processes but does not support multi-threading (clarify this first). If it is a file operation, you only need to lock the file and no other operations are required. , PHP flock has already done it for you.

Use flock to lock the file before writing, and unlock it after writing. This allows multiple threads to read and write a file at the same time to avoid conflicts. It's probably the following process

/*
*flock(file,lock,block)
*file 必需，规定要锁定或释放的已打开的文件
*lock 必需。规定要使用哪种锁定类型。
*block 可选。若设置为 1 或 true，则当进行锁定时阻挡其他进程。
*lock
*LOCK_SH 要取得共享锁定（读取的程序）
*LOCK_EX 要取得独占锁定（写入的程序）
*LOCK_UN 要释放锁定（无论共享或独占）
*LOCK_NB 如果不希望 flock() 在锁定时堵塞
/*
if (flock($file,LOCK_EX))
{
fwrite($file,'write more words');
flock($file,LOCK_UN);
}
else
{
//处理错误逻辑
}
fclose($file);
)

For more related knowledge, please visit PHP Chinese website! !

The above is the detailed content of How does PHP solve the problem of multiple processes reading and writing a file at the same time?. For more information, please follow other related articles on the PHP Chinese website!