Pipe /createpipe

Hello everyone , I meet you again , I'm the king of the whole stack , I wish every programmer can learn more languages .

BOOL CreatePipe(PHANDLE hReadPipe, // Pointer to the read handle 　PHANDLE hWritePipe, // Pointer to the write handle 　LPSECURITY_ATTRIBUTES lpPipeAttributes, // Pointer to a security property 　DWORD nSize // Pipe size );

The Conduit （Pipe） It is actually a piece of shared memory for inter process communication , The process of creating a pipeline is called pipeline server, The process connected to a pipeline is the pipeline client . A process writes data to the pipeline , Another process can read it from the other end of the pipe . Anonymous pipeline （Anonymous Pipes） It is an unnamed pipeline for one-way data transmission between parent and child processes , It can only be used in the local computer , It can not be used for communication between networks .

The Conduit server take lpPipeAttributes Point to the SECURITY_ATTRIBUTES Data members of data structures bInheritHandle Set to TRUE, that CreatePipe（） Created pipeline read 、 The write handle will be inherited

The parent process can call the process creation function CreateProcess（） Generate subprocesses . Suppose the parent process wants to send data to the child process , The parent process can call WriteFile（） Write data to the pipeline （ Pass pipeline write handle to function ）, Child process calls GetStdHandle（） Get the read handle of the pipeline , Pass this handle into ReadFile（） Then read the data from the pipe .

　　 Suppose that the parent process reads data from the child process , Then the child process calls GetStdHandle（） Get the write handle of the pipeline , And call WriteFile（） Write data to the pipeline . then , Parent process call ReadFile（） Read data from the pipe （ Pass pipeline read handle to function ）.

In use WriteFile（） When the function writes data to the pipeline , The function returns only after writing the specified byte of data to the pipeline or when an error occurs . If the pipeline buffer is full and the data has not been written ,WriteFile（） It will not return until another process reads the data in the pipeline to free up a lot of other available space . The Conduit server Calling CreatePipe（） Create the pipe with parameters nSize The buffer size of the pipe is set .

　　 Anonymous pipes do not support asynchronous reads 、 Write operations , This means that you can't use... In anonymous pipes ReadFileEx（） and WriteFileEx（）, also ReadFile（） and WriteFile（） Medium lpOverLapped Parameters will also be ignored . The anonymous pipeline will read 、 Exit after all write handles are closed , It can also be called in the process CloseHandle（） Function to close this handle .

Publisher ： Full stack programmer stack length , Reprint please indicate the source ：https://javaforall.cn/118215.html Link to the original text ：https://javaforall.cn