curl/docs/libcurl/opts/CURLOPT_RESUME_FROM.md
Daniel Stenberg e694c8284a
docs/libcurl/opts: clarify the return values
Expand a little.

- mention the type name of the return code
- avoid stating which exact return codes that might be returned, as that
  varies over time, builds and conditions
- avoid stating some always return OK
- refer to the manpage documenting all the return codes

Closes #15900
2025-01-02 17:13:33 +01:00

83 lines
1.8 KiB
Markdown

---
c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Title: CURLOPT_RESUME_FROM
Section: 3
Source: libcurl
See-also:
- CURLOPT_INFILESIZE (3)
- CURLOPT_RANGE (3)
- CURLOPT_RESUME_FROM_LARGE (3)
Protocol:
- All
Added-in: 7.1
---
# NAME
CURLOPT_RESUME_FROM - offset to resume transfer from
# SYNOPSIS
~~~c
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_RESUME_FROM, long from);
~~~
# DESCRIPTION
Pass a long as parameter. It contains the offset in number of bytes that you
want the transfer to start from. Set this option to 0 to make the transfer
start from the beginning (effectively disabling resume). For FTP, set this
option to -1 to make the transfer start from the end of the target file
(useful to continue an interrupted upload).
When doing uploads with FTP, the resume position is where in the local/source
file libcurl should try to resume the upload from and it then appends the
source file to the remote target file.
If you need to resume a transfer beyond the 2GB limit, use
CURLOPT_RESUME_FROM_LARGE(3) instead.
# DEFAULT
0, not used
# %PROTOCOLS%
# EXAMPLE
~~~c
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
long size_of_file;
curl_easy_setopt(curl, CURLOPT_URL, "ftp://example.com");
/* resume upload at byte index 200 */
curl_easy_setopt(curl, CURLOPT_RESUME_FROM, 200L);
/* ask for upload */
curl_easy_setopt(curl, CURLOPT_UPLOAD, 1L);
/* set total data amount to expect */
curl_easy_setopt(curl, CURLOPT_INFILESIZE, size_of_file);
/* Perform the request */
curl_easy_perform(curl);
}
}
~~~
# %AVAILABILITY%
# 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).