How to convert pid_t to string

c, pid

Solution

Instead of using `strcat` to build a string, consider using the much more flexible (and efficient!) `sprintf`/`snprintf` function instead:

char *end = str;
end += sprintf(end, "%s ", "hello!");
end += sprintf(end, "%ld", (long)getpid());
if(bar)
    end += sprintf(end, "%x", 0xf00d);

Observe that `sprintf` returns the number of characters written, so you can build a string without succumbing to Schlemiel the Painter's algorithm. If you want to ensure that you don't overrun a buffer of fixed size, `snprintf` will do this for you (`strcat` will just blindly concatenate, and there is no standard way to avoid that).

Note that the `pid_t` standard guarantees that there are "one or more programming environments in which the [width] of `pid_t`... is no greater than the width of type `long`". Therefore, casting `pid_t` to `long` is safe as long as `getconf` says so.

Problem

So, I need to strcat pid to some string. I have this ``` strcat (str,(char*)getpid()); ``` but this doesn't work. ----edit---- ok i understand the downvotes. i was too quick to post a question. and didnt realize pid returns an int and i can't cast an int to char* itoa doesnt work because it is not standart c. this is how i did it. ``` char pid[10]; snprintf(pid, 10,"%d",(int)getpid()); strcat (str, pid); ```

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