Loading docs/libcurl/libcurl-tutorial.3 +13 −9 Original line number Original line Diff line number Diff line Loading @@ -195,20 +195,24 @@ and the function that gets invoked by libcurl. libcurl itself won't touch the data you pass with CURLOPT_WRITEDATA. data you pass with CURLOPT_WRITEDATA. libcurl offers its own default internal callback that'll take care of the data libcurl offers its own default internal callback that'll take care of the data if you don't set the callback with CURLOPT_WRITEFUNCTION. It will then simply if you don't set the callback with \fICURLOPT_WRITEFUNCTION\fP. It will then output the received data to stdout. You can have the default callback write simply output the received data to stdout. You can have the default callback the data to a different file handle by passing a 'FILE *' to a file opened for write the data to a different file handle by passing a 'FILE *' to a file writing with the CURLOPT_WRITEDATA option. opened for writing with the \fICURLOPT_WRITEDATA\fP option. Now, we need to take a step back and have a deep breath. Here's one of those Now, we need to take a step back and have a deep breath. Here's one of those rare platform-dependent nitpicks. Did you spot it? On some platforms[2], rare platform-dependent nitpicks. Did you spot it? On some platforms[2], libcurl won't be able to operate on files opened by the program. Thus, if you libcurl won't be able to operate on files opened by the program. Thus, if you use the default callback and pass in a an open file with CURLOPT_WRITEDATA, it use the default callback and pass in a an open file with will crash. You should therefore avoid this to make your program run fine \fICURLOPT_WRITEDATA\fP, it will crash. You should therefore avoid this to virtually everywhere. make your program run fine virtually everywhere. (CURLOPT_WRITEDATA was formerly known as CURLOPT_FILE. Both names still work (\fICURLOPT_WRITEDATA\fP was formerly known as \fICURLOPT_FILE\fP. Both names and do the same thing). still work and do the same thing). If you're using libcurl as a win32 DLL, you MUST use the \fICURLOPT_WRITEFUNCTION\fP if you set \fICURLOPT_WRITEDATA\fP - or you will experience crashes. There are of course many more options you can set, and we'll get back to a few There are of course many more options you can set, and we'll get back to a few of them later. Let's instead continue to the actual transfer: of them later. Let's instead continue to the actual transfer: Loading Loading
docs/libcurl/libcurl-tutorial.3 +13 −9 Original line number Original line Diff line number Diff line Loading @@ -195,20 +195,24 @@ and the function that gets invoked by libcurl. libcurl itself won't touch the data you pass with CURLOPT_WRITEDATA. data you pass with CURLOPT_WRITEDATA. libcurl offers its own default internal callback that'll take care of the data libcurl offers its own default internal callback that'll take care of the data if you don't set the callback with CURLOPT_WRITEFUNCTION. It will then simply if you don't set the callback with \fICURLOPT_WRITEFUNCTION\fP. It will then output the received data to stdout. You can have the default callback write simply output the received data to stdout. You can have the default callback the data to a different file handle by passing a 'FILE *' to a file opened for write the data to a different file handle by passing a 'FILE *' to a file writing with the CURLOPT_WRITEDATA option. opened for writing with the \fICURLOPT_WRITEDATA\fP option. Now, we need to take a step back and have a deep breath. Here's one of those Now, we need to take a step back and have a deep breath. Here's one of those rare platform-dependent nitpicks. Did you spot it? On some platforms[2], rare platform-dependent nitpicks. Did you spot it? On some platforms[2], libcurl won't be able to operate on files opened by the program. Thus, if you libcurl won't be able to operate on files opened by the program. Thus, if you use the default callback and pass in a an open file with CURLOPT_WRITEDATA, it use the default callback and pass in a an open file with will crash. You should therefore avoid this to make your program run fine \fICURLOPT_WRITEDATA\fP, it will crash. You should therefore avoid this to virtually everywhere. make your program run fine virtually everywhere. (CURLOPT_WRITEDATA was formerly known as CURLOPT_FILE. Both names still work (\fICURLOPT_WRITEDATA\fP was formerly known as \fICURLOPT_FILE\fP. Both names and do the same thing). still work and do the same thing). If you're using libcurl as a win32 DLL, you MUST use the \fICURLOPT_WRITEFUNCTION\fP if you set \fICURLOPT_WRITEDATA\fP - or you will experience crashes. There are of course many more options you can set, and we'll get back to a few There are of course many more options you can set, and we'll get back to a few of them later. Let's instead continue to the actual transfer: of them later. Let's instead continue to the actual transfer: Loading
