XFree(3) XLIB FUNCTIONS XFree(3)NAMEXFree - free client data
int XFree(void *data);
data Specifies the data that are to be freed.
The XFree function is a general-purpose Xlib routine that frees the
specified data. You must use it to free any objects that were allo‐
cated by Xlib, unless an alternate function is explicitly specified for
the object. A NULL pointer cannot be passed to this function.
Xlib - C Language X Interface
X Version 11 libX11 1.3.5 XFree(3)