Re: [PATCH] regex.3: Add example program

[Alejandro Colomar <colomar.6.4.3@gmail.com>]

I realized now that the output is a bit weird:
I'm printing the offset incorrectly (except for the first match).
I'll fix it in a few minutes.

Thanks,

Alex

On 10/17/20 3:13 PM, Alejandro Colomar wrote:
> $ gcc -Wall -Wextra -Werror -pedantic regex.c -o regex
> $ ./regex
> String = "1) John Driverhacker;
> 2) John Doe;
> 3) John Foo;
> "
> #0 match:
> rm_so = 25; rm_eo = 32; len = 7
> substring = "John Do"
> #1 match:
> rm_so = 6; rm_eo = 14; len = 8
> substring = "John Foo"
> 
> Signed-off-by: Alejandro Colomar <colomar.6.4.3@gmail.com>
> ---
> 
> Hello Michael,
> 
> Here's the example for regex.3 :-}
> 
> Best regards,
> 
> Alex
> 
> 
>  man3/regex.3 | 44 ++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 44 insertions(+)
> 
> diff --git a/man3/regex.3 b/man3/regex.3
> index 7c5132995..94da88b7e 100644
> --- a/man3/regex.3
> +++ b/man3/regex.3
> @@ -337,6 +337,50 @@ T}	Thread safety	MT-Safe
>  .TE
>  .SH CONFORMING TO
>  POSIX.1-2001, POSIX.1-2008.
> +.SH EXAMPLES
> +.EX
> +#include <stddef.h>
> +#include <stdint.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <regex.h>
> +
> +#define ARRAY_SIZE(arr) (sizeof((arr)) / sizeof((arr)[0]))
> +
> +static const char *const str =
> +        "1) John Driverhacker;\en2) John Doe;\en3) John Foo;\en";
> +static const char *const re = "John.*o";
> +
> +int main(void)
> +{
> +    static const char *s = str;
> +    regex_t     regex;
> +    regmatch_t  pmatch[1];
> +    regoff_t    len;
> +
> +    if (regcomp(&regex, re, REG_NEWLINE))
> +        exit(EXIT_FAILURE);
> +
> +    printf("String = \\"%s\\"\en", str);
> +
> +    for (ptrdiff_t i = 0; ; i++) {
> +        if (regexec(&regex, s, ARRAY_SIZE(pmatch), pmatch, 0))
> +            break;
> +
> +        len = pmatch[0].rm_eo \- pmatch[0].rm_so;
> +        printf("#%td match:\en", i);
> +        printf("rm_so = %jd; rm_eo = %jd; len = %jd\en",
> +                (intmax_t) pmatch[0].rm_so,
> +                (intmax_t) pmatch[0].rm_eo,
> +                (intmax_t) len);
> +        printf("substring = \\"%.*s\\"\en", len, s + pmatch[0].rm_so);
> +
> +        s += pmatch[0].rm_eo;
> +    }
> +
> +    exit(EXIT_SUCCESS);
> +}
> +.EE
>  .SH SEE ALSO
>  .BR grep (1),
>  .BR regex (7)
>