Title: Question about mmap? -- Linux general technology-Linux programming and kernel information. The following is a detailed description. At the beginning, I learned about linux programming. I don't know much about some basic issues.
I have read the original form of the mmap function void * mmap (void * addr, size_t length, int prot, int flags, int fd, off_t offset );
The rest are quite understandable, and the port and flags are a bit problematic.
The name of prot indicates the int type. How can I use PORT_RDONLY or another port in actual applications. I think this prot is similar to the linux File Permission. In this example, the port parameter is changed to the {0-7} numeric mode based on the File Permission. After compilation, the port parameter still passes, and it seems that the execution is fine. I want to know if this approach is correct.
There is also a flag, which also shows the int type. Can it also be replaced by numbers?
At last, mmap must have the root permission during compilation. I read an article saying that as long as the flag selects a value, it can be compiled with the common user permission. Is that true?
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