qsharedmemory between Qt and c program on linux plateform

[marwan]

Thank you wysota for help
but, i want to know if i should use the Qsahredmemory functions(create(),setkey(),attach(),lock()) or shm functions (chmget(),shmat()...); personnaly i prefer use the first choice because it's more simple and acces management to the memory respected.

[wysota]

It doesn't matter as long as you interchange APIs that are compatible. What Qt does is it takes a file path you pass as the key, calls ftok() on it (with 'Q' as the proj_id parameter) and then uses the result with shmget(). Your code bypasses the first two steps thus you don't have a valid key.