CURLOPT_ACCEPT_ENCODING not working (help)

Hi,

I’m using a self built libcurl shared library for embedded use in a C++ application. In the attempt of requesting it to automatically decompress response data from a remote server of interest by using a line like the following in my request setup:

curl_easy_setopt(mpCURL, CURLOPT_ACCEPT_ENCODING, "gzip");

The returned data seems to remain compressed. I enabled the CURLOPT_HEADER option and can see that the server returns positive Content-Lengths, with few non-human readable characters in the body content. To be clear, removing the CURLOPT_ACCEPT_ENCODING option doesn’t make any difference.

The libcurl library compilation is done in a custom automated CI/CD in the cloud which also compiles OpenSSL and ZLib as shared libraries in separate pipelines, with libcurl pipeline pulling from the master branch (from official libcurl’s repo) and a compilation script like the following:

cmake -Bbuild -DBUILD_SHARED_LIBS=OFF -DCMAKE_BUILD_TYPE=MinSizeRel -DCMAKE_POSITION_INDEPENDENT_CODE=ON -DCURL_DISABLE_COOKIES=ON -DCURL_DISABLE_CRYPTO_AUTH=ON -DCURL_DISABLE_LDAP=ON -DCURL_DISABLE_PROXY=ON -DENABLE_IPV6=OFF -DENABLE_UNIX_SOCKETS=OFF -DHTTP_ONLY=ON -DOPENSSL_CRYPTO_LIBRARY=$(Pipeline.Workspace)/ssl/lib/libcrypto.so.1.1 -DOPENSSL_INCLUDE_DIR=$(Pipeline.Workspace)/ssl/include -DOPENSSL_SSL_LIBRARY=$(Pipeline.Workspace)/ssl/lib/libssl.so.1.1 -DZLIB_INCLUDE_DIR=$(Pipeline.Workspace)/zlib/include -DZLIB_LIBRARY=$(Pipeline.Workspace)/zlib/lib/libz.so.1 . && cmake --build build

I can see the following possible relevant build output lines (not contiguous) that may indicate ZLib gets correctly integrated:

Found ZLIB: /home/vsts/work/1/zlib/lib/libz.so.1 (found version "1.2.11")

Enabled features: SSL libz AsynchDNS alt-svc HTTPS-proxy

However, I’ve seen in the following answer: https://stackoverflow.com/a/29966893. Looking at my generated libcurl headers, I can’t find any match for “HAVE_LIBZ” (neither in my build output).

What could I be doing wrong? Many thanks.

Best regards,

Adrián