Dag-Erling Smorgrav <des@flood.ping.uio.no> writes:
> -	    if ((realpat = malloc(strlen(pattern) + sizeof("^(") +
> -				  sizeof(")$") + 1)) == NULL)
> -		err(1, "malloc");
> +	    realpat = grep_malloc(strlen(pattern) + sizeof("^(")
> +				  + sizeof(")$") + 1);
>  	    strcpy(realpat, "^(");
>  	    strcat(realpat, pattern);
>  	    strcat(realpat, ")$");

Why not just use asprintf?

> +void *
> +grep_malloc(size_t size)
> +{
> +    void *ptr;
> +
> +    if ((ptr = malloc(size)) == NULL) {
> +	errno = ENOMEM;
> +	err(1, "malloc");
> +    }
> +    return ptr;
> +}

In this case it doesn't matter but in general this function is wrong.
malloc(0) can return NULL.

And besides, I really don't think this is a grep function but actually
is useful for programs that don't have any strategy for handling out
of memory errors and might as well die (with a descriptive error
message, of course).  Let's call it emalloc and let's put in somewhere
where it can be used.

void *
emalloc (size_t sz)
{
    void *tmp = malloc (sz);

    if (tmp == NULL && sz != 0) {
        errno = ENOMEM;
	err (1, "malloc %lu", (unsigned long)sz);
    }
    return tmp;
}

/assar