getaliasbyname_r - Linux
Overview
getaliasbyname_r is a Linux command used to retrieve alias information for a specified name or alias. It is commonly used in networking and system administration for managing aliases and resolving domain names.
Syntax
int getaliasbyname_r(const char *name, struct hostent *result, char *buffer, size_t buflen, int *h_errnop);
Options/Flags
| Option | Description | Default |
|—|—|—|
| name | The name or alias to lookup. | |
| result | A pointer to a hostent structure to receive the alias information. | |
| buffer | A buffer to store the returned data. | |
| buflen | The size of the buffer. | |
| h_errnop | A pointer to a variable that will receive an error code. | |
Examples
Lookup alias information for a given name:
#include <netdb.h>
int main() {
struct hostent *result;
char buffer[1024];
int h_errnop;
if (getaliasbyname_r("example.com", result, buffer, sizeof(buffer), &h_errnop) == 0) {
printf("Alias information for example.com:\n");
printf("Name: %s\n", result->h_name);
printf("Aliases: ");
for (char **alias = result->h_aliases; *alias != NULL; alias++) {
printf("%s ", *alias);
}
printf("\n");
} else {
printf("Error: %s\n", hstrerror(h_errnop));
}
return 0;
}
Common Issues
Error code 1 (HOST_NOT_FOUND): The specified name or alias does not exist.
Error code 3 (TRY_AGAIN): The DNS server is temporarily unavailable. Retry later.
Integration
getaliasbyname_r can be combined with other commands for advanced tasks:
- nslookup to perform DNS lookups:
nslookup example.com | getaliasbyname_r -
Related Commands
- gethostbyname_r – Retrieve host information from a name.
- getaddrinfo – Resolve a host name or service name to a list of addresses.
- dns – Perform DNS lookups and administration.