---
name: "CURLOPT_PROXY_CAINFO"
section: "3"
platform: "macos"
package: "curl"
version: "166.0.0.0.1"
release: "macOS 26.5"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_PROXY_CAINFO"
---

# CURLOPT\_PROXY\_CAINFO(3)

path to proxy Certificate Authority (CA) bundle

## NAME

CURLOPT\_PROXY\_CAINFO - path to proxy Certificate Authority (CA) bundle

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_CAINFO, char *path);
```

## DESCRIPTION

This option is for connecting to an HTTPS proxy, not an HTTPS server.

Pass a char pointer to a null-terminated string naming a file holding one or more certificates to verify the HTTPS proxy with.

If *[CURLOPT\_PROXY\_SSL\_VERIFYPEER(3)](/CURLOPT_PROXY_SSL_VERIFYPEER/3.md)* is zero and you avoid verifying the server's certificate, *[CURLOPT\_PROXY\_CAINFO(3)](/CURLOPT_PROXY_CAINFO/3.md)* need not even indicate an accessible file.

This option is by default set to the system path where libcurl's CA certificate bundle is assumed to be stored, as established at build time.

(iOS and macOS only) If curl is built against Secure Transport, then this option is supported for backward compatibility with other SSL engines, but it should not be set. If the option is not set, then curl uses the certificates in the system and user Keychain to verify the peer, which is the preferred method of verifying the peer's certificate chain.

The application does not have to keep the string around after setting this option.

The default value for this can be figured out with *[CURLINFO\_CAINFO(3)](/CURLINFO_CAINFO/3.md)*.

## DEFAULT

Built-in system specific

## PROTOCOLS

Used with HTTPS proxy

## EXAMPLE

```
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    /* using an HTTPS proxy */
    curl_easy_setopt(curl, CURLOPT_PROXY, "https://localhost:443");
    curl_easy_setopt(curl, CURLOPT_PROXY_CAINFO, "/etc/certs/cabundle.pem");
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
```

## AVAILABILITY

Added in 7.52.0

For TLS backends that do not support certificate files, the *[CURLOPT\_PROXY\_CAINFO(3)](/CURLOPT_PROXY_CAINFO/3.md)* option is ignored. Refer to https://curl.se/docs/ssl-compared.html

## RETURN VALUE

Returns CURLE\_OK if the option is supported, CURLE\_UNKNOWN\_OPTION if not, or CURLE\_OUT\_OF\_MEMORY if there was insufficient heap space.

## SEE ALSO

[**CURLOPT\_CAINFO**(3)](/CURLOPT_CAINFO/3.md), [**CURLOPT\_CAINFO\_BLOB**(3)](/CURLOPT_CAINFO_BLOB/3.md), [**CURLOPT\_CAPATH**(3)](/CURLOPT_CAPATH/3.md), [**CURLOPT\_PROXY\_CAINFO\_BLOB**(3)](/CURLOPT_PROXY_CAINFO_BLOB/3.md), [**CURLOPT\_PROXY\_CAPATH**(3)](/CURLOPT_PROXY_CAPATH/3.md), [**CURLOPT\_PROXY\_SSL\_VERIFYHOST**(3)](/CURLOPT_PROXY_SSL_VERIFYHOST/3.md), [**CURLOPT\_PROXY\_SSL\_VERIFYPEER**(3)](/CURLOPT_PROXY_SSL_VERIFYPEER/3.md), [**CURLOPT\_SSL\_VERIFYHOST**(3)](/CURLOPT_SSL_VERIFYHOST/3.md), [**CURLOPT\_SSL\_VERIFYPEER**(3)](/CURLOPT_SSL_VERIFYPEER/3.md)