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.
That's true. fattrib function doesnt have any declaration in the rtl.h but the documentation says otherwise.
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 */