sprintf question

[rtnMichael]

ok, why does this give me a bus error?
int mail_num = 0;
char mail_text_array[9999];
...
...
...

mail_function(f,p1,p2,p3,p4,p5,p6,p7,p8,p9)
char *f;
{
sprintf(mail_text_array[mail_num],f,p1,p2,p3,p4,p5,p6,p7,p8,p9);

mail_num++;
}


when this does it just fine:

char mail_text[10];

...
...
...

mail_function(f,p1,p2,p3,p4,p5,p6,p7,p8,p9)
char *f;
{
sprintf(mail_text,f,p1,p2,p3,p4,p5,p6,p7,p8,p9);
}


Can somebody explain?

Thanks
M

 

[nkm]

Hi

1) sprintf requires a char * as the first argument

When you are doing mail_text_array[mail_num] you are pointing to a value in the array which is wrong because it is a char not a char *.
&mail_text_array[mail_num] would have worked. But then mail_num should be 0 otherwise it'll start writing from some random location in the string.

2) Also when it says 2nd argument as const char * what it
expects is the format string that is "%s%s%d" etc... you should not just pass any char pointer. It could lead to runtime errors.

so change your sprintf to

sprintf(mail_text, "%s%s%s%s%s%s%s%s%s%s", p1, p2, p3, p4, p5, p6, p7, p8, p9); I assume all p's are char arrays.

3) Also you need to make sure that mail_text has enough space to accomodate the entire string. Otherwise it could lead to runtime errors.

 

[dchoulette]

Try:

char mail_text_array[9999][10];

 

[rtnMichael]

Thanks for the suggestions nkm and dchoulette, but the *f is a char string that is somewhat like a printf statement in itself. Maybe I don't know what I'm talking about, but let me show you what I mean:

// call to function //
mail_num = 0;
mail_function(1,FLAGIT,"%s exists but not %s or %s", var1_path, var2_path, var3_path);

// function //
static int mail_function(level, flagit, f, p1,p2,p3,p4,p5,p6,p7,p8,p9)
char *f;
{
if(printf("%c%s - ",flagit? '+':' ',fmt_time()) == -1)
goto err;

if(printf(f,p1,p2,p3,p4,p5,p6,p7,p8,p9) == -1 || putchar('\n') == EOF || fflush(stdout) == EOF)
{
err: (void) fprintf(stderr,"%s: error %d - %s.\n",
process_name,errno, strerror(errno));

(void) fprintf(stderr,"%s: Can't produce log messages.\n", process_name);
(void) fprintf(stderr,"%s: Terminating.", process_name);
exit(2);
}

if(level <= log_level)
{
// MAX_INPUTS = 10 //
if (mail_num >= MAX_INPUTS)
mail_num = 0;

sprintf(mail_text,f,p1,p2,p3,p4,p5,p6,p7,p8,p9);

mail_text_array[mail_num]=(char *)malloc(strlen(mail_text)+1);
strcpy(mail_text_array[mail_num], mail_text);
mail_num++;
}
return(0);
}

I figured out another way to do it, both with the sprintf first and a strcpy to an array afterwards. I know this may not be the most clean way to do it, but hey, I'm dealing with a deadline here so whatever works in the program works for the company. ;-)

Anyway, thanks for the help!
Mike