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fs.read documentation does not specify how to detect EOF condition #35363

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joepie91 opened this issue Sep 26, 2020 · 1 comment · Fixed by #35445
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fs.read documentation does not specify how to detect EOF condition #35363

joepie91 opened this issue Sep 26, 2020 · 1 comment · Fixed by #35445
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doc Issues and PRs related to the documentations. fs Issues and PRs related to the fs subsystem / file system.

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@joepie91
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joepie91 commented Sep 26, 2020 •
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As far as I can tell, neither fs.read nor FileHandle#read specify how to detect when the end of a file has been reached, nor can I find this information elsewhere in the fs documentation.

The fs.createReadStream implementation suggests that the answer to this question is "when bytesRead is 0", but this should be added to the documentation if that is indeed the correct way to detect this condition.
@ChALkeR ChALkeR added doc Issues and PRs related to the documentations. fs Issues and PRs related to the fs subsystem / file system. labels Sep 26, 2020
@bnoordhuis
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The docs probably implicitly assume familiarity with man 2 read but to not keep you in suspense any longer: you detect it by observing a short read (fewer bytes than you requested, possibly zero) but, caveat emptor, the next read can return more bytes if the file was modified concurrently.

Documentation pull request welcome.

@lpinca lpinca mentioned this issue Oct 1, 2020
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@lpinca lpinca closed this as completed in 0f9170e Oct 4, 2020
danielleadams pushed a commit that referenced this issue Oct 6, 2020
@lpinca @danielleadams
doc: specify how to detect EOF
e40876a 
Specify how to detect end-of-file when using `fs.read()` and
`filehandle.read()`.

PR-URL: #35445
Fixes: #35363
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Zeyu Yang <himself65@outlook.com>
Reviewed-By: Andrey Pechkurov <apechkurov@gmail.com>
joesepi pushed a commit to joesepi/node that referenced this issue Jan 8, 2021
@lpinca @joesepi
doc: specify how to detect EOF
ea57774 
Specify how to detect end-of-file when using `fs.read()` and
`filehandle.read()`.

PR-URL: nodejs#35445
Fixes: nodejs#35363
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Zeyu Yang <himself65@outlook.com>
Reviewed-By: Andrey Pechkurov <apechkurov@gmail.com>
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doc: specify how to detect EOF lpinca/node
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@bnoordhuis @ChALkeR @joepie91