Re: [PATCH] mallopt.3: fix program source to match behaviour example

["Michael Kerrisk (man-pages)" <mtk.manpages@xxxxxxxxx>]

On Mon, Apr 30, 2012 at 12:07 AM, Simon Paillard <spaillard@xxxxxxxxxx> wrote:
> Call mallopt with argv[1] only if a parameter is given
> ---
>  man3/mallopt.3 |    8 ++++----
>  1 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/man3/mallopt.3 b/man3/mallopt.3
> index ddb1aed..03f1e9a 100644
> --- a/man3/mallopt.3
> +++ b/man3/mallopt.3
> @@ -543,11 +543,11 @@ main(int argc, char *argv[])
>             fprintf(stderr, "%s <M_CHECK_ACTION\-value>\\n", argv[0]);
>             exit(EXIT_FAILURE);
>         }
> -    }
>
> -    if (mallopt(M_CHECK_ACTION, atoi(argv[1])) != 1) {
> -        fprintf(stderr, "mallopt() failed");
> -        exit(EXIT_FAILURE);
> +        if (mallopt(M_CHECK_ACTION, atoi(argv[1])) != 1) {
> +            fprintf(stderr, "mallopt() failed");
> +            exit(EXIT_FAILURE);
> +        }
>     }
>
>     p = malloc(1000);
> --

Hi Simon,

Thanks for this. Somewhere along the way I included the wrong source
in the EXAMPLE section. However, the intended code was as per this
patch:

==
--- a/man3/mallopt.3
+++ b/man3/mallopt.3
@@ -540,17 +540,12 @@ main(int argc, char *argv[])
     char *p;

     if (argc > 1) {
-        if (argc != 2) {
-            fprintf(stderr, "%s <M_CHECK_ACTION\-value>\\n", argv[0]);
+        if (mallopt(M_CHECK_ACTION, atoi(argv[1])) != 1) {
+            fprintf(stderr, "mallopt() failed");
             exit(EXIT_FAILURE);
         }
     }

-    if (mallopt(M_CHECK_ACTION, atoi(argv[1])) != 1) {
-        fprintf(stderr, "mallopt() failed");
-        exit(EXIT_FAILURE);
-    }
-
     p = malloc(1000);
     if (p == NULL) {
         fprintf(stderr, "malloc() failed");
==

The complete example is shown below. I've applied the above patch.

Cheers,

Michael

=====

#include <malloc.h>
#include <stdio.h>
#include <stdlib.h>

int
main(int argc, char *argv[])
{
    char *p;

    if (argc > 1) {
        if (mallopt(M_CHECK_ACTION, atoi(argv[1])) != 1) {
            fprintf(stderr, "mallopt() failed");
            exit(EXIT_FAILURE);
        }
    }

    p = malloc(1000);
    if (p == NULL) {
        fprintf(stderr, "malloc() failed");
        exit(EXIT_FAILURE);
    }

    free(p);
    printf("main(): returned from first free() call\n");

    free(p);
    printf("main(): returned from second free() call\n");

    exit(EXIT_SUCCESS);
}


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Author of "The Linux Programming Interface"; http://man7.org/tlpi/
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