getprotobyname_r - Linux
Overview
getprotobyname_r is a standard C library function used to retrieve information about a network protocol based on its name. It is part of the Berkeley Software Distribution (BSD) sockets API and is commonly used to obtain protocol-related details for network programming.
Syntax
int getprotobyname_r(const char *name, struct protoent *result, char *buffer, size_t buflen, struct protoent **resultp);
Options/Flags
- name: The name of the protocol to be retrieved.
- result: A pointer to a
protoent
structure where the protocol information will be stored. - buffer: A buffer to hold the information retrieved.
- buflen: The size of the buffer.
- resultp: A pointer to the
protoent
structure returned, orNULL
if the protocol is not found.
Examples
#include <stdio.h>
#include <netdb.h>
int main() {
struct protoent *proto;
char buffer[1024];
if (getprotobyname_r("tcp", proto, buffer, sizeof(buffer), &proto) == 0) {
printf("Protocol number: %d\n", proto->p_proto);
} else {
printf("Protocol not found\n");
}
return 0;
}
Common Issues
- Ensure that the buffer provided is large enough to hold the returned information.
- Verify that the name of the protocol is correct.
Integration
getprotobyname_r can be combined with other networking commands, such as getsockopt
and setsockopt
, to configure and manipulate network connections.
Related Commands
- getprotobynumber_r: Retrieves protocol information based on its number.
- getservbyname_r: Retrieves service information based on its name.