improper printf in semaphore

Asked May 02 '22 at 07:39

Active May 02 '22 at 07:39

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i have a log function which is called just after sem_post(&sem_ptr):

sem_post(&sem_ptr);
write(STD_OUT, "blah", 5);

when i use these sequence of code, i mean calling write after sem_post, sometimes the "blah" string is printed twice, but when i use the following sequence of code:

write(STD_OUT, "blah", 5);
sem_post(&sem_ptr);

the output is correct and the "blah" string is printed once. can somebody explain this behaviour?

asked May 02 '22 at 07:39

CaptainHb

`sem_post` unlocks your semaphore - that is why the second code example works as expected. – fpmurphy May 02 '22 at 07:54
@fpmurphy ok but why it is printed twice? just for this reason? – CaptainHb May 02 '22 at 07:59
To figure that out, you need to supply a minimum reproducible example. – fpmurphy May 02 '22 at 11:37

improper printf in semaphore

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