diff options
| -rw-r--r-- | docs/libcurl/curl_easy_setopt.3 | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/docs/libcurl/curl_easy_setopt.3 b/docs/libcurl/curl_easy_setopt.3 index 3b804a1f6..e5ca09f4b 100644 --- a/docs/libcurl/curl_easy_setopt.3 +++ b/docs/libcurl/curl_easy_setopt.3 @@ -342,11 +342,15 @@ argument in the closesocket callback set with The default value of this parameter is unspecified. (Option added in 7.21.7) .IP CURLOPT_PROGRESSFUNCTION -Pass a pointer to a function that matches the following prototype: \fBint -function(void *clientp, double dltotal, double dlnow, double ultotal, double -ulnow); \fP. This function gets called by libcurl instead of its internal -equivalent with a frequent interval during operation (roughly once per second -or sooner) no matter if data is being transferred or not. +Pass a pointer to a function that matches the following prototype: + +\fBint function(void *clientp, double dltotal, double dlnow, double ultotal, +double ulnow);\fP + +This function gets called by libcurl instead of its internal equivalent with a +frequent interval. While data is being transferred it will be called very +frequently, and during slow periods like when nothing is being transferred it +can slow down to about one call per second. \fIclientp\fP is the pointer set with \fICURLOPT_PROGRESSDATA\fP, it is not actually used by libcurl but is only passed along from the application to the @@ -360,7 +364,9 @@ expects to upload in this transfer. \fIulnow\fP is the number of bytes uploaded so far. Unknown/unused argument values passed to the callback will be set to zero -(like if you only download data, the upload size will remain 0). +(like if you only download data, the upload size will remain 0). Many times +the callback will be called one or more times first, before it knows the data +sizes so a program must be made to handle that. Returning a non-zero value from this callback will cause libcurl to abort the transfer and return \fICURLE_ABORTED_BY_CALLBACK\fP. |