shown above.
CURLOPT_DEBUGFUNCTION(3) replaces the standard debug function used when
-CURLOPT_VERBOSE(3) is in effect. This callback receives debug
-information, as specified in the *type* argument. This function must
-return 0. The *data* pointed to by the char * passed to this function is
-not null-terminated, but is exactly of the *size* as told by the
-*size* argument.
+CURLOPT_VERBOSE(3) is in effect. This callback receives debug information, as
+specified in the *type* argument. This function must return 0. The *data*
+pointed to by the char * passed to this function is not null-terminated, but
+is exactly of the *size* as told by the *size* argument.
+
+**WARNING** this callback may receive sensitive contents from headers and
+data, including information sent as **CURLINFO_TEXT**.
The *clientp* argument is the pointer set with CURLOPT_DEBUGDATA(3).
# DESCRIPTION
-Set the *onoff* parameter to 1 to make the library display a lot of
-verbose information about its operations on this *handle*. Useful for
-libcurl and/or protocol debugging and understanding. The verbose information
-is sent to stderr, or the stream set with CURLOPT_STDERR(3).
+Set the *onoff* parameter to 1 to make the library display a lot of verbose
+information about its operations on this *handle*. Useful for libcurl and/or
+protocol debugging and understanding. The verbose information is sent to
+stderr, or the stream set with CURLOPT_STDERR(3).
You hardly ever want this enabled in production use, you almost always want
this used when you debug/report problems.
To also get all the protocol data sent and received, consider using the
CURLOPT_DEBUGFUNCTION(3).
+**WARNING** this may show sensitive contents from headers and data.
+
# DEFAULT
0, meaning disabled.