Re: Memory mapping: MAP_PRIVATE and msync()

On 2024-04-08, Lawrence D'Oliveiro <ldo@nz.invalid> wrote:

On Sun, 07 Apr 24 15:18:47 +0000, pehache wrote:
>

void* p2 = mmap( NULL
                   , n
                   , PROT_READ | PROT_WRITE
                   , MAP_SHARED | MAP_NORESERVE
                   , fd
                   , 0 );

>
Not easy to remember what the arguments mean. Try this:

Nobody is going to follow your grotesque, poorly considered coding
conventions.

>
    void * p2 = mmap
      (
        /*addr =*/ NULL,

            ^^^^     ^^^^ a null pointer is some kind of "addr"

        /*length =*/ n,
        /*prot =*/ PROT_READ | PROT_WRITE,

            ^^^^     ^^^^
             |         |
             `---------|---- You know this
                       `---- from this.
                       

        /*flags =*/ MAP_SHARED | MAP_NORESERVE,

            ^^^^
            Tells you nothing. You know that preprocessor constants
            combined together with | are "flags".

        /*fd =*/ fd,

            ^^     ^^
             identical, tells you nothing.

        /*offset =*/ 0
      );

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