in klog.go [598:615]
func (l *loggingT) header(s severity, depth int) (*buffer, string, int) {
_, file, line, ok := runtime.Caller(3 + depth)
if !ok {
file = "???"
line = 1
} else {
if slash := strings.LastIndex(file, "/"); slash >= 0 {
path := file
file = path[slash+1:]
if l.addDirHeader {
if dirsep := strings.LastIndex(path[:slash], "/"); dirsep >= 0 {
file = path[dirsep+1:]
}
}
}
}
return l.formatHeader(s, file, line), file, line
}