What is the advantage of setting a file attribute to "S" i.e. system file? I just came across a document which describes what letter sets what attribute.
In the latest RTL.h fattrib is declared on line 423.
Name: RTL.H Rev.: V4.73 Line 423: extern int fattrib (const char *par, const char *path);
Mine is v4.53 and line 423 reads - #define TCP_TYPE_FLOW_CTRL 0x08 /* Socket Type Flow Control */