CURLOPT\_EXPECT\_100\_TIMEOUT\_MS(3) Library Functions Manual CURLOPT\_EXPECT\_100\_TIMEOUT\_MS(3)

# [NAME](#NAME)

CURLOPT\_EXPECT\_100\_TIMEOUT\_MS - timeout for Expect: 100-continue response

# [SYNOPSIS](#SYNOPSIS)

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_EXPECT_100_TIMEOUT_MS,


                          long milliseconds);
```

# [DESCRIPTION](#DESCRIPTION)

Pass a long to tell libcurl the number of *milliseconds* to wait for a server response with the HTTP status 100 (Continue), 417 (Expectation Failed) or similar after sending an HTTP request containing an Expect: 100-continue header. If this times out before a response is received, the request body is sent anyway.

# [DEFAULT](#DEFAULT)

1000 milliseconds

# [PROTOCOLS](#PROTOCOLS)

This functionality affects http only

# [EXAMPLE](#EXAMPLE)

```
int main(void)
{


  CURL *curl = curl_easy_init();


  if(curl) {


    CURLcode result;


    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");


    /* wait 3 seconds for 100-continue */


    curl_easy_setopt(curl, CURLOPT_EXPECT_100_TIMEOUT_MS, 3000L);


    result = curl_easy_perform(curl);


    curl_easy_cleanup(curl);


  }
}
```

# [AVAILABILITY](#AVAILABILITY)

Added in curl 7.36.0

# [RETURN VALUE](#RETURN_VALUE)

[*curl\_easy\_setopt(3)*](/man/os/curl/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)*](/man/os/curl/libcurl-errors.3).

# [SEE ALSO](#SEE_ALSO)

[**CURLOPT\_HTTPPOST**(3)](/man/os/curl/CURLOPT_HTTPPOST.3), [**CURLOPT\_POST**(3)](/man/os/curl/CURLOPT_POST.3)

2026-10-19 libcurl

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Document: CURLOPT_EXPECT_100_TIMEOUT_MS(3) from curl 8.23.0-r1 (Chainguard OS)
Source: https://github.com/curl/curl.git