get a protocol entry, given a number
#include <netdb.h> struct protoent *getprotobynumber( int proto );
The getprotobynumber() function gets the protocol entry for the given number. It returns a pointer to structure of type protoent, which contains the broken-out fields of a line in the network protocol database, /etc/protocols.
The getprotobyname() and getprotobynumber() functions sequentially search from the beginning of the file until a matching protocol name or protocol number is found, or until EOF is encountered.
A pointer to a valid protoent structure, or NULL if an error occurs.
POSIX 1003.1g (draft)
| Safety: | |
|---|---|
| Interrupt handler | No |
| Signal handler | No |
| Thread | No |
This function uses static data; if the data is needed for future use, it should be copied before any subsequent calls overwrite it.
Currently, only the Internet protocols are understood.
endprotoent(), getprotobyname(), getprotoent(), protoent, setprotoent()
/etc/protocols in the TCP/IP User's Guide