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.

Using this option multiple times makes the last set string override the previous ones. Set it to NULL to disable its use again.

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).