The callbacks were partially documented to support this. Now the
behavior is documented and returning error from either of these
callbacks will effectively kill all currently ongoing transfers.
Added test 530 to verify
Reported-by: Marcelo Juchem
Fixes#8083Closes#8089
- replace tabs with spaces where possible
- remove line ending spaces
- remove double/triple newlines at EOF
- fix a non-UTF-8 character
- cleanup a few indentations/line continuations
in manual examples
Closes https://github.com/curl/curl/pull/3037