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From: "Lavrentiev, Anton (NIH/NLM/NCBI) [C]" <lavr@ncbi.nlm.nih.gov>
To: Matthew Rickard <rickard.matt@gmail.com>,
	Csaba Raduly <rcsaba@gmail.com>, cygwin list <cygwin@cygwin.com>
Subject: RE: [EXTERNAL] Re: 3.4.6-1 shm_open always returns -1, errno EINVAL
Date: Mon, 13 Mar 2023 15:07:28 +0000	[thread overview]
Message-ID: <DM8PR09MB70951EDCB7281743462401F3A5B99@DM8PR09MB7095.namprd09.prod.outlook.com> (raw)
In-Reply-To: <9ee76b85-9d35-8e30-43b4-5bfd51ff78fb@gmail.com>

> > returns 3 and sets errno to zero.

Note that "setting errno to zero" is not guaranteed in case of a successful completion of a library function or a system call.
Generally, "errno" reflects an error that occurred last when such a call failed (so in other words, in case of a successful
completion, "errno" can still carry over an error from a previously failed call).  In this particular use case, it looks like
"errno" was clear from the get go because nothing was called prior to "shm_open()", and so it remained so when the call returned (successfully).

HTH,

Anton Lavrentiev
Contractor NIH/NLM/NCBI


      reply	other threads:[~2023-03-13 15:16 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-12  6:44 Matthew Rickard
2023-03-12 10:35 ` Csaba Raduly
2023-03-12 22:55   ` Matthew Rickard
2023-03-13 15:07     ` Lavrentiev, Anton (NIH/NLM/NCBI) [C] [this message]

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