CURLOPT_USERAGENT - Man Page

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_USERAGENT, char *ua);

Pass a pointer to a null-terminated string as parameter. It is used to set the User-Agent: header field in the HTTP request sent to the remote server. You can also set any custom header with CURLOPT_HTTPHEADER(3).

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

NULL, no User-Agent: header is used.

This functionality affects http only

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

    curl_easy_setopt(curl, CURLOPT_USERAGENT, "Dark Secret Ninja/1.0");

    curl_easy_perform(curl);
  }
}

Added in curl 7.1

Returns CURLE_OK if HTTP is supported, CURLE_UNKNOWN_OPTION if not, or CURLE_OUT_OF_MEMORY if there was insufficient heap space.

CURLOPT_CUSTOMREQUEST(3), CURLOPT_HTTPHEADER(3), CURLOPT_REFERER(3), CURLOPT_REQUEST_TARGET(3)

curl_easy_setopt(3), CURLOPT_HTTPHEADER(3), CURLOPT_REFERER(3), libcurl-security(3), libcurl-symbols(3), nbdkit-curl-plugin(1).