CURLOPT_USERAGENT(3) - Man pages

CURLOPT_USERAGENT(3)        Library Functions Manual       CURLOPT_USERAGENT(3)

NAME
       CURLOPT_USERAGENT - HTTP user-agent header

SYNOPSIS
       #include <curl/curl.h>

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

DESCRIPTION
       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.

DEFAULT
       NULL, no User-Agent: header is used.

PROTOCOLS
       This functionality affects http only

EXAMPLE
       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);
         }
       }

AVAILABILITY
       Added in curl 7.1

RETURN VALUE
       curl_easy_setopt(3) returns a CURLcode indicating success or error.

       CURLE_OK  (0) means everything was OK, non-zero means an error occurred,
       see libcurl-errors(3).

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

libcurl                            2026-07-12              CURLOPT_USERAGENT(3)

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