Calculate the free size of a directory using statvfs and statvfs64

statvfs.c

#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <sys/statvfs.h>

static int print_bytes_free_32( const char* directory )
{
	struct statvfs buf32;
	if ( statvfs( directory, &buf32 ) == -1 )
	{
		fprintf( stderr, "statvfs: %s (%d)\n", strerror( errno ), errno );
		return 0;
	}

	int64_t free32 = (uint64_t)buf32.f_frsize * (uint64_t)buf32.f_bfree;

	printf( "Using statvfs:\n" );
	printf( "    File system block size: %d\n", buf32.f_frsize );
	printf( "    Blocks free: %d\n", buf32.f_bfree );
	printf( "    Bytes free: %lld\n", free32 );

	return 1;
}

static int print_bytes_free_64( const char* directory )
{
	struct statvfs64 buf64;
	if ( statvfs64( directory, &buf64 ) == -1 )
	{
		fprintf( stderr, "statvfs64: %s (%d)\n", strerror( errno ), errno );
		return 0;
	}

	int64_t free64 = buf64.f_frsize * buf64.f_bfree;

	printf( "Using statvfs64:\n" );
	printf( "    File system block size: %lld\n", buf64.f_frsize );
	printf( "    Blocks free: %lld\n", buf64.f_bfree );
	printf( "    Bytes free: %lld\n", free64 );

	return 1;
}

int main( int argc, const char* argv[] )
{
	if ( argc != 2 )
	{
		fprintf( stderr, "Usage: %s <directory>\n", argv[0] );
		return 1;
	}

	if ( !print_bytes_free_32( argv[1] ) )
		return 1;

	printf( "\n" );

	if ( !print_bytes_free_64( argv[1] ) )
		return 1;

	return 0;
}