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CURLOPT_CHUNK_BGN_FUNCTION(3)                         curl_easy_setopt options

NAME

CURLOPT_CHUNK_BGN_FUNCTION - callback before a transfer with FTP wildcardmatch

SYNOPSIS

#include <curl/curl.h> struct curl_fileinfo { char *filename; curlfiletype filetype; time_t time; /* always zero! */ unsigned int perm; int uid; int gid; curl_off_t size; long int hardlinks; struct { /* If some of these fields is not NULL, it is a pointer to b_data. */ char *time; char *perm; char *user; char *group; char *target; /* pointer to the target filename of a symlink */ } strings; unsigned int flags; /* used internally */ char *b_data; size_t b_size; size_t b_used; }; long chunk_bgn_callback(const void *transfer_info, void *ptr, int remains); CURLcode curl_easy_setopt(CURL *handle, CURLOPT_CHUNK_BGN_FUNCTION, chunk_bgn_callback);

DESCRIPTION

Pass a pointer to your callback function, which should match the prototype shown above. This callback function gets called by libcurl before a part of the stream is going to be transferred (if the transfer supports chunks). The transfer_info pointer will point to a struct curl_fileinfo with details about the file that is about to get transferred. This callback makes sense only when using the CURLOPT_WILDCARDMATCH(3) option for now. The target of transfer_info parameter is a "feature depended" structure. For the FTP wildcard download, the target is curl_fileinfo structure (see curl/curl.h). The parameter ptr is a pointer given by CURLOPT_CHUNK_DATA(3). The parameter remains contains number of chunks remaining per the transfer. If the feature is not available, the parameter has zero value. Return CURL_CHUNK_BGN_FUNC_OK if everything is fine, CURL_CHUNK_BGN_FUNC_SKIP if you want to skip the concrete chunk or CURL_CHUNK_BGN_FUNC_FAIL to tell libcurl to stop if some error occurred.

DEFAULT

NULL

PROTOCOLS

FTP

EXAMPLE

static long file_is_coming(struct curl_fileinfo *finfo, struct callback_data *data, int remains) { printf("%3d %40s %10luB ", remains, finfo->filename, (unsigned long)finfo->size); switch(finfo->filetype) { case CURLFILETYPE_DIRECTORY: printf(" DIR\n"); break; case CURLFILETYPE_FILE: printf("FILE "); break; default: printf("OTHER\n"); break; } if(finfo->filetype == CURLFILETYPE_FILE) { /* do not transfer files >= 50B */ if(finfo->size > 50) { printf("SKIPPED\n"); return CURL_CHUNK_BGN_FUNC_SKIP; } data->output = fopen(finfo->filename, "wb"); if(!data->output) { return CURL_CHUNK_BGN_FUNC_FAIL; } } return CURL_CHUNK_BGN_FUNC_OK; } int main() { /* data for callback */ struct callback_data callback_info; /* callback is called before download of concrete file started */ curl_easy_setopt(curl, CURLOPT_CHUNK_BGN_FUNCTION, file_is_coming); curl_easy_setopt(curl, CURLOPT_CHUNK_DATA, &callback_info); }

AVAILABILITY

This was added in 7.21.0

RETURN VALUE

Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

SEE ALSO

CURLOPT_CHUNK_END_FUNCTION(3), CURLOPT_WILDCARDMATCH(3), libcurl 7.66.0 May 3, 2019 CURLOPT_CHUNK_BGN_FUNCTION(3)

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