#include "apue.h"#include <errno.h>#include <limits.h>#ifdef	PATH_MAXstatic int	pathmax = PATH_MAX;#elsestatic int	pathmax = 0;#endif#define SUSV3	200112Lstatic long	posix_version = 0;/* If PATH_MAX is indeterminate, no guarantee this is adequate */#define	PATH_MAX_GUESS	1024char *path_alloc(int *sizep) /* also return allocated size, if nonnull */{	char	*ptr;	int	size;	if (posix_version == 0)		posix_version = sysconf(_SC_VERSION);	if (pathmax == 0) {		/* first time through */		errno = 0;		if ((pathmax = pathconf("/", _PC_PATH_MAX)) < 0) {			if (errno == 0)				pathmax = PATH_MAX_GUESS;	/* it's indeterminate */			else				err_sys("pathconf error for _PC_PATH_MAX");		} else {			pathmax++;		/* add one since it's relative to root */		}	}	if (posix_version < SUSV3)		size = pathmax + 1;	else		size = pathmax;	if ((ptr = malloc(size)) == NULL)		err_sys("malloc error for pathname");	if (sizep != NULL)		*sizep = size;	return(ptr);}