Px_ipc_name()函数

/* include px_ipc_name */
#include        "unpipc.h"

char *
px_ipc_name(const char *name)
{
        char    *dir, *dst, *slash;
        //分配的空间在哪里释放的哦！@deprecated 
        if ( (dst = malloc(PATH_MAX)) == NULL)
                return(NULL);

                /* 4can override default directory with environment variable */
        if ( (dir = getenv("PX_IPC_NAME")) == NULL) {
#ifdef  POSIX_IPC_PREFIX
                dir = POSIX_IPC_PREFIX;         /* from "config.h" */
#else
                dir = "/tmp";                           /* default */
#endif
        }
                /* 4dir must end in a slash */
        slash = (dir[strlen(dir) - 1] == '/') ? "" : "/";
        snprintf(dst, PATH_MAX, "%s%s%s", dir, slash, name);

        return(dst);                    /* caller can free() this pointer */
}
/* end px_ipc_name */

char *
Px_ipc_name(const char *name)
{
        char    *ptr;
        // gcc -posix -E -dM - </dev/null >
#ifdef linux
        ptr = (char *)name;
#else
        if ( (ptr = px_ipc_name(name)) == NULL)
                err_sys("px_ipc_name error for %s", name);
#endif
        return(ptr);
}