[C言語]ホスト名

#include <stdio.h>

int main(void){
	char cpnm[MAX_COMPUTERNAME_LENGTH+1];
	DWORD len;

	len=MAX_COMPUTERNAME_LENGTH+1;

	GetComputerName(cpnm,&len);
	printf("this computer name is %s\n", cpnm);


	return 0;
}

$ gcc -o main main.c
main.c: In function ‘main’:
main.c:4:12: error: ‘MAX_COMPUTERNAME_LENGTH’ undeclared (first use in this function)
char cpnm[MAX_COMPUTERNAME_LENGTH+1];
^~~~~~~~~~~~~~~~~~~~~~~
main.c:4:12: note: each undeclared identifier is reported only once for each function it appears in
main.c:5:2: error: unknown type name ‘DWORD’
DWORD len;
^~~~~
main.c:9:2: warning: implicit declaration of function ‘GetComputerName’ [-Wimplicit-function-declaration]
GetComputerName(cpnm,&len);
^~~~~~~~~~~~~~~

GetComputerNameではなく、gethostnameか。

#include <stdio.h>
#include <unistd.h> // インプリメンテーション固有関数

int main(void){
	char hostname[128];

	gethostname(hostname, sizeof(hostname));

	printf("host name is %s\n", hostname);

	return 0;
}

$ ./main
host name is ubuntu-bionic

ほうー