CURLOPT_MAXFILESIZE(3) Introduction to Library Functions CURLOPT_MAXFILESIZE(3)

CURLOPT_MAXFILESIZE - maximum file size allowed to download

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_MAXFILESIZE, long size);

Pass a long as parameter. This specifies the maximum accepted size (in bytes) of a file to download. If the file requested is found larger than this value, the transfer is aborted and CURLE_FILESIZE_EXCEEDED is returned. Passing a zero size disables this, and passing a negative size yields a CURLE_BAD_FUNCTION_ARGUMENT.

If you want a limit above 2GB, use CURLOPT_MAXFILESIZE_LARGE(3).

If the size is known to be too big before the transfer starts, libcurl aborts before starting the transfer. If it is instead found to be too big while the transfer is in progress, libcurl aborts the transfer once the received bytes exceed the limit.

Since 8.20.0, this option also aborts ongoing transfers once the decompressed bytes exceed this threshold due to automatic decompression using CURLOPT_ACCEPT_ENCODING(3).

0, meaning disabled.

This functionality affects all supported protocols

int main(void)
{

CURL *curl = curl_easy_init();
if(curl) {
CURLcode result;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
/* refuse to download if larger than 1000 bytes */
curl_easy_setopt(curl, CURLOPT_MAXFILESIZE, 1000L);
result = curl_easy_perform(curl);
} }

Added in curl 7.10.8

Before curl 8.4.0, the limit was not applied to transfers in progress.

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).

CURLOPT_MAXFILESIZE_LARGE(3), CURLOPT_MAX_RECV_SPEED_LARGE(3)

2026-08-09 libcurl