- Name: Wu Yanzhen
- Student ID: 201821121034
- Class: Calculate 1812
1. Write a program
Vim write programs on the server: Create a named pipe, two processes are created for the pipeline to read fifo_read.cand write fifo_write.c. (Given the source code)
(1) Read the fifo_read.c program, the source code is as follows:
(2) Write the fifo_write.c program, the source code is as follows:
2. Analyze the operation results
(1) Operation result:
(2) Analysis:
Open two terminals and run the read and write programs simultaneously. Cyclic input of content, the content can be read out sequentially through the reading program
mkfifo () function:
int mkfifo(const char *filename,mode_t mode)
· The required header files are: #include <sys / types.h> #include <sys / stat.h>
·mode:
O_RDONLY: read pipeline
O_WRONLY: write pipeline
O_RDWR: read and write pipeline
O_NONBLOCK: non-blocking
· If the function is successfully executed, the return value is 0, otherwise it is -1
3. Generate new questions and answers through this experiment
Question: Congestion issues related to pipeline reading and writing
Answer: O_NONBLOCK in the open () function, indicating a non-blocking flag
- For the reading process: when the pipeline is blocked, if there is no data in the FIFO, the process will block until data is written; when the pipeline is not blocked, the reading process will be executed immediately, if the FIFO has no data, the function will return 0
- For the write process: in the case of a blocked pipeline, the write operation will block until the data can be written; in the case of the pipeline is not blocked but cannot write all the data, the read operation partially writes or the call fails