strerror.3: Add an example for perror()

[0mp]

Summary

strerror.3: Add an example for perror()

This is a nice and quick reference.

[yuripv]

lib/libc/string/strerror.3

158 ↗

(On Diff #80725)

[0mp]

main(void)

[0mp]

Thank you

[0mp]

@yuripv, let me know if that's a nice addition to the manual page or not. :) I understand it's basic stuff, but I feel like it's nice to show common patterns in a manual for reference.

[0mp]

Hmm, maybe it's better to keep the example shorter as in the err(3) manual page?

[yuripv]

In D27623#617254, @0mp wrote:

@yuripv, let me know if that's a nice addition to the manual page or not. :) I understand it's basic stuff, but I feel like it's nice to show common patterns in a manual for reference.

it is nice addition indeed, every little bit helps

[yuripv]

In D27623#617271, @0mp wrote:

Hmm, maybe it's better to keep the example shorter as in the err(3) manual page?

not sure, both works for me.

p.s. as you mentioned err(3), i think there an error in "Warn of an error" example -- second one uses err().

[jilles]

lib/libc/string/strerror.3

161 ↗

(On Diff #80727)

This is not a great example since it is undefined behaviour. In fact, before FreeBSD 11.0, this caused a segmentation fault instead of an error return.

Perhaps a better example is fd = open("/dev/null/wrong", O_RDONLY); which will fail with Not a directory.

[0mp]

lib/libc/string/strerror.3

161 ↗

(On Diff #80727)

Ha, fascinating! Thanks a lot, I'll update the revision shortly.

[0mp]

Use open() instead of pipe().

[0mp]

Thanks!