---
name: "CURLOPT_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_CAINFO_BLOB"
---

# CURLOPT\_CAINFO\_BLOB(3)

Certificate Authority (CA) bundle in PEM format

## NAME

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

## SYNOPSIS

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

## DESCRIPTION

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 server 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\_SSL\_VERIFYPEER(3)](/CURLOPT_SSL_VERIFYPEER/3.md)* is zero and you avoid verifying the server's certificate, *[CURLOPT\_CAINFO\_BLOB(3)](/CURLOPT_CAINFO_BLOB/3.md)* is not needed.

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

## DEFAULT

NULL

## PROTOCOLS

All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

## EXAMPLE

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

## AVAILABILITY

Added in 7.77.0.

This option is supported by the BearSSL (since 7.79.0), mbedTLS (since 7.81.0), rustls (since 7.82.0), wolfSSL (since 8.2.0), 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\_CAPATH**(3)](/CURLOPT_CAPATH/3.md), [**CURLOPT\_SSL\_VERIFYHOST**(3)](/CURLOPT_SSL_VERIFYHOST/3.md), [**CURLOPT\_SSL\_VERIFYPEER**(3)](/CURLOPT_SSL_VERIFYPEER/3.md)