Semaphore Question?

SDL Development
1

When working with Semaphore, if you get an error when calling
SDL_SemWait() or SDL_SemPost(), what could this indicate?

Should I handle it gracefully with an ‘if’ statement, or is simply an
assert, good enough? I was thinking of speed you see, when I’m sure it
all runs well with no Semaphore errors, I could just add -DNDEBUG, to
skip all the semaphore checks.

Any advice anyone?

Arthur.

2

When working with Semaphore, if you get an error when calling
SDL_SemWait() or SDL_SemPost(), what could this indicate?

Should I handle it gracefully with an ‘if’ statement, or is simply an
assert, good enough? I was thinking of speed you see, when I’m sure it
all runs well with no Semaphore errors, I could just add -DNDEBUG, to
skip all the semaphore checks.

I’ve never seen an error with the semaphore operations. Have you?
I think an assert would be fine.

See ya,
-Sam Lantinga, Lead Programmer, Loki Entertainment Software

3

When working with Semaphore, if you get an error when calling
SDL_SemWait() or SDL_SemPost(), what could this indicate?
Should I handle it gracefully with an ‘if’ statement, or is simply
an

assert, good enough? I was thinking of speed you see, when I’m
sure it

all runs well with no Semaphore errors, I could just add -DNDEBUG,
to

skip all the semaphore checks.
I’ve never seen an error with the semaphore operations. Have you?
I think an assert would be fine.

Agreed. I looked at the source for Win32 and it’s unclear (in MSDN)
why WaitForSingleObject would fail, except if the handle to the
semaphore was invalid (ie: you forgot to call SDL_CreateSemaphore or
you somehow overwrote the memory of your struct). I imagine it would
be similar on other platforms.–

Olivier A. Dagenais - Software Architect and Developer

4

In article <9b50l9$oi4$1 at ftp.lokigames.com>, “Olivier Dagenais”
<olivier.dagenais at canada.com> wrote:

When working with Semaphore, if you get an error when calling
SDL_SemWait() or SDL_SemPost(), what could this indicate? Should I
handle it gracefully with an ‘if’ statement, or is simply
an

assert, good enough? I was thinking of speed you see, when I’m
sure it

all runs well with no Semaphore errors, I could just add -DNDEBUG,
to

skip all the semaphore checks.
I’ve never seen an error with the semaphore operations. Have you? I
think an assert would be fine.

Agreed. I looked at the source for Win32 and it’s unclear (in MSDN) why
WaitForSingleObject would fail, except if the handle to the semaphore
was invalid (ie: you forgot to call SDL_CreateSemaphore or you somehow
overwrote the memory of your struct). I imagine it would be similar on
other platforms.

And since errors like that should be ironed out in debugging, assert will
do. :slight_smile:
That’ll elliminate a shit load of ‘if’s’, that are called constantly.

Defensive programming is best, but you got to draw a line somewhere when
you want to write games that go like the clappers.

Arthur.