---
name: "CURLOPT_PROXY_CAINFO_BLOB"
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_BLOB"
---

# CURLOPT\_PROXY\_CAINFO\_BLOB(3)

proxy Certificate Authority (CA) bundle in PEM format

## NAME

CURLOPT\_PROXY\_CAINFO\_BLOB - proxy Certificate Authority (CA) bundle in PEM format

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_CAINFO_BLOB,
                          struct curl_blob *stblob);
```

## DESCRIPTION

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

Pass a pointer to a curl\_blob structure, which contains information (pointer and size) about a memory block with binary data of PEM encoded content holding one or more certificates to verify the HTTPS proxy with.

If the blob is initialized with the flags member of struct curl\_blob set to CURL\_BLOB\_COPY, the application does not have to keep the buffer around after setting this.

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\_BLOB(3)](/CURLOPT_PROXY_CAINFO_BLOB/3.md)* is not needed.

This option overrides *[CURLOPT\_PROXY\_CAINFO(3)](/CURLOPT_PROXY_CAINFO/3.md)*.

## DEFAULT

NULL

## PROTOCOLS

Used with HTTPS proxy

## EXAMPLE

```
#include <string.h> /* for strlen */
extern char *strpem; /* strpem must point to a PEM string */
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    struct curl_blob blob;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    /* using an HTTPS proxy */
    curl_easy_setopt(curl, CURLOPT_PROXY, "https://localhost:443");
    blob.data = strpem;
    blob.len = strlen(strpem);
    blob.flags = CURL_BLOB_COPY;
    curl_easy_setopt(curl, CURLOPT_PROXY_CAINFO_BLOB, &blob);
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
```

## AVAILABILITY

Added in 7.77.0.

This option is supported by the rustls (since 7.82.0), OpenSSL, Secure Transport and Schannel backends.

## 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**(3)](/CURLOPT_PROXY_CAINFO/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)