1--- 2c: Copyright (C) Daniel Stenberg, <daniel.se>, et al. 3SPDX-License-Identifier: curl 4Title: curl_formget 5Section: 3 6Source: libcurl 7See-also: 8 - curl_formadd (3) 9 - curl_mime_init (3) 10--- 11 12# NAME 13 14curl_formget - serialize a previously built multipart form POST chain 15 16# SYNOPSIS 17 18~~~c 19#include <curl/curl.h> 20 21int curl_formget(struct curl_httppost * form, void *userp, 22 curl_formget_callback append); 23~~~ 24 25# DESCRIPTION 26 27curl_formget() serializes data previously built with curl_formadd(3). It 28accepts a void pointer as second argument named *userp* which is passed as 29the first argument to the curl_formget_callback function. 30 31~~~c 32 typedef size_t (*curl_formget_callback)(void *userp, const char *buf, 33 size_t len);" 34~~~ 35 36The curl_formget_callback is invoked for each part of the HTTP POST chain. The 37character buffer passed to the callback must not be freed. The callback should 38return the buffer length passed to it on success. 39 40If the **CURLFORM_STREAM** option is used in the formpost, it prevents 41curl_formget(3) from working until you have performed the actual HTTP 42request. This, because first then does libcurl known which actual read 43callback to use! 44 45# EXAMPLE 46 47~~~c 48size_t print_httppost_callback(void *arg, const char *buf, size_t len) 49{ 50 fwrite(buf, len, 1, stdout); 51 (*(size_t *) arg) += len; 52 return len; 53} 54 55size_t print_httppost(struct curl_httppost *post) 56{ 57 size_t total_size = 0; 58 if(curl_formget(post, &total_size, print_httppost_callback)) { 59 return (size_t) -1; 60 } 61 return total_size; 62} 63~~~ 64 65# AVAILABILITY 66 67This function was added in libcurl 7.15.5. The form API is deprecated in 68libcurl 7.56.0. 69 70# RETURN VALUE 71 720 means everything was OK, non-zero means an error occurred 73