---
name: "CURLOPT_EXPECT_100_TIMEOUT_MS"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_EXPECT_100_TIMEOUT_MS"
---

# CURLOPT\_EXPECT\_100\_TIMEOUT\_MS(3)

timeout for Expect: 100-continue response

## NAME

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

## SYNOPSIS

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

## 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

1000 milliseconds

## PROTOCOLS

This functionality affects http only

## 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

Added in curl 7.36.0

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLOPT\_HTTPPOST**(3)](/CURLOPT_HTTPPOST/3.md), [**CURLOPT\_POST**(3)](/CURLOPT_POST/3.md)