getrpcent_r - Linux

Overview

getrpcent_r() is a BSD-derived C library function used to obtain the next RPC service entry in the hosts’ database. It provides a thread-safe alternative to getrpcent() by performing operations in a reentrant manner.

Syntax

int getrpcent_r(struct rpcent **result, char *buffer, size_t buflen, struct rpcent **rpc);

Options/Flags

None.

Examples

Simple Example

#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>

int main() {
    struct rpcent *rpc;
    char buffer[256];
    struct rpcent *result;

    while (getrpcent_r(&result, buffer, sizeof(buffer), &rpc) == 0) {
        printf("rpc name: %s\n", result->r_name);
        printf("rpc number: %d\n", result->r_number);
    }

    return 0;
}

Complex Example

This example shows how to use getrpcent_r() to find a specific RPC service by name:

#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>

int main() {
    char buffer[256];
    struct rpcent *rpc;
    struct rpcent *result;

    while (getrpcent_r(&result, buffer, sizeof(buffer), &rpc) == 0) {
        if (strcmp(result->r_name, "nfs") == 0) {
            printf("NFS service found: %s, port %d\n", result->r_name, result->r_number);
            break;
        }
    }

    return 0;
}

Common Issues

One common issue when using getrpcent_r() is ensuring that the buffer passed is large enough to hold the entire RPC service entry. If the buffer is too small, the function will return -1 and set errno to ERANGE.

Integration

getrpcent_r() can be used with other networking-related commands and functions, such as setnetent, getnetent, and endnetent.

Related Commands

• getrpcent: Non-reentrant version of getrpcent_r()
• getnetbyname: Obtains network entry by name
• getservbyname: Obtains service entry by name