chore: Failed to create instance #202
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Sometimes Ubuntu20.04-24.04 execution of `d->memory->attach()` crashes here and prints the necessary information to determine that the creation has failed
| @@ -72,8 +72,9 @@ SingleApplication::SingleApplication( int &argc, char *argv[], bool allowSeconda | |||
| #else | |||
| d->memory = new QSharedMemory( d->blockServerName ); | |||
| #endif | |||
| d->memory->attach(); | |||
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When debugging and releasing, there is a high probability that this line will crash after a few more tries;
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Being able to see that d->memory->attach(): true
Shared memory creation failed: "QSharedMemory::attach (shm_open): already exists"
Successfully attached to existing shared memory block
Memory block successfully locked
Shared memory data doesn't NULL!
Primary: true "0x1" ← see
Secondary: 0 "0x0" ← see
Primary PID: 9425 "0x24D1"
Checksum: 5070 "0x13CE"
Primary User: vincentJust skipped the associated judgment and final execution exit |
| bool ok = d->memory->attach(); | ||
| qCritical() << "d->memory->attach():" << ok; | ||
| if (ok) delete d->memory; |
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That first attach and delete are dummy operations. They are only there as I noticed that when there is orphaned shared memory after the original process has crashed, attaching and deleting clears it up. If it's not orphaned this is a no-op.
As such I didn't think I need to check their success status.
| @@ -91,23 +92,46 @@ SingleApplication::SingleApplication( int &argc, char *argv[], bool allowSeconda | |||
| } | |||
| d->initializeMemoryBlock(); | |||
| } else { | |||
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| qCritical() << "Shared memory creation failed:" << d->memory->errorString(); | |||
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This is a valid code path when there is already an instance running. There is no need for qCritical here.
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Why? Why do you want all these unnecessary and misleading |
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When the creation fails (constructor), nothing logs neither prints. It can be very confusing. An example process is shown in the video at #201 |
Sometimes Ubuntu20.04-24.04 execution of
d->memory->attach()crashes here and prints the necessary information to determine that the creation has failed