`curl_easy_getinfo` type checking failed

[Billyzou0741326]

I was using the CURLOPT_PRIVATE to store some data. Here's what I did,

struct http_request_private_data *priv_data;
curl_easy_getinfo(easy_curl, CURLINFO_PRIVATE, &priv_data);

But then when I compiled with Linux gcc, I got this error (as in issue #846),

curl/typecheck-gcc.h:122:13: error: call to ‘_curl_easy_getinfo_err_string’ declared with attribute warning: curl_easy_getinfo expects a pointer to 'char *' for this info [-Werror]
             _curl_easy_getinfo_err_string();

Curiously, there was no warning when I compiled with -O0 flag, without making any changes to the code.
When using any other optimization flags, -O2 for instance, the warning shows up.

curl/libcurl version

curl-config --version
libcurl 7.70.0

operating system

Linux 4.15.0-91-generic #92-Ubuntu SMP Fri Feb 28 11:09:48 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

[bagder]

Ack. CURLINFO_PRIVATE is set to have a CURLINFO_STRING type which then leads to that. We can't change the number now but we can add an exception to typecheck-gcc.h.

Thanks for this report!

[bagder]

Uh, why close it?

[bagder]

@Billyzou0741326 can you check if the fix in #5436 is fine for you?

[minamiktr]

Yes, compiled successfully. Thank you!