-readn function implementation of Linux network programming

Readn function function: In the network programming reading data, usually will need to use a read the specified byte to return the function, the Linux system call did not give, need to own encapsulation.

READN Implementation code:

intREADN (intFdvoid*vptr, size_t N) {size_t Nleft= N;//the READN function also needs to read the number of bytesssize_t nread =0;//the Read function reads the number of bytesUnsignedChar*ptr = (Char*) vptr;//Pointer to buffer     while(Nleft >0) {nread=Read (FD, PTR, nleft); if(-1==nread) {            if(Eintr = =errno) Nread=0; Else                return-1; }        Else if(0==nread) {             Break; } nleft-=nread; PTR+=nread; }    returnN-Nleft;}

-readn function implementation of Linux network programming