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Asked: 2026-05-11T09:27:52+00:00

I would like to pass a pointer (I am putting a file with data

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I would like to pass a pointer (I am putting a file with data in memory with mmap) to processes spawned using fork + exec, but I am stuck on how to pass a pointer to the exec() spawned process?

UPDATE1:

Thanks for your inputs, I do use shared memory creating it with mmap with MAP_INHERIT flag:

Each mapped file and shared memory region created with the mmap() function is unmapped by a successful call to any of the exec functions, except those regions mapped with the MAP_INHERIT option. Regions mapped with the MAP_INHERIT option remain mapped in the new process image.

source: http://www.uwm.edu/cgi-bin/IMT/wwwman?topic=exec(2)&msection=

UPDATE2:

This is homework excercise, but I think I must stop thinking about pointers and think about the IPC itself. I guess I will go with trying to mmap the same file in child process.

Short code example much appreciated.

Thanks in advance for your help.

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  1. If you use shared memory, you can’t pass the pointer. The pointer will contain the virtual address, which is different from one process to another. You have to exchange offset values, based on the start of the shared memory area.

    If you don’t use shared memory, you can’t exchange pointers of any kind: The other process won’t be able to access the memory of your process.

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