g_prefix_error (
  GError** err,
  const gchar* format,


Formats a string according to format and prefix it to an existing error message. If err is NULL (ie: no error variable) then do nothing.

If *err is NULL (ie: an error variable is present but there is no error condition) then also do nothing.

Available since:2.16
This function is not directly available to language bindings


err GError

A return location for a GError.

 The argument will be modified by the function.
 The argument can be set to NULL.
 The argument can be NULL.
 The called function takes ownership of the data, and is responsible for freeing it.
format const gchar*

Printf()-style format string.

 The data is owned by the caller of the function.
 The value is a NUL terminated UTF-8 string.

Arguments to format.