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| .TH CURLOPT_CHUNK_BGN_FUNCTION 3 "May 03, 2019" "libcurl 7.73.0" "curl_easy_setopt options" |
| |
| .SH NAME |
| CURLOPT_CHUNK_BGN_FUNCTION \- callback before a transfer with FTP wildcardmatch |
| .SH SYNOPSIS |
| .nf |
| #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); |
| .SH 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 \fItransfer_info\fP 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 \fICURLOPT_WILDCARDMATCH(3)\fP |
| 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 |
| \fIcurl/curl.h\fP). The parameter \fIptr\fP is a pointer given by |
| \fICURLOPT_CHUNK_DATA(3)\fP. The parameter remains contains number of chunks |
| remaining per the transfer. If the feature is not available, the parameter has |
| zero value. |
| |
| Return \fICURL_CHUNK_BGN_FUNC_OK\fP if everything is fine, |
| \fICURL_CHUNK_BGN_FUNC_SKIP\fP if you want to skip the concrete chunk or |
| \fICURL_CHUNK_BGN_FUNC_FAIL\fP to tell libcurl to stop if some error occurred. |
| .SH DEFAULT |
| NULL |
| .SH PROTOCOLS |
| FTP |
| .SH EXAMPLE |
| .nf |
| 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); |
| } |
| .fi |
| .SH AVAILABILITY |
| This was added in 7.21.0 |
| .SH RETURN VALUE |
| Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. |
| .SH "SEE ALSO" |
| .BR CURLOPT_CHUNK_END_FUNCTION "(3), " CURLOPT_WILDCARDMATCH "(3), " |