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Groups > comp.lang.c > #43612

Re: errno

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First:

The line

>    printf("%d\n", a);

seems to be wrong. As a is long int, it should read

    printf("%ld\n", a);
             ^ mind the 'l'

Second:

As I understand 'man strtol' on my system, strtol sets errno only in
case of underflow or overflow, in which case it returns LONG_MIN or
respectively LONG_MAX.

So checking for -1 doesn't detect an error situation. You should
check for LONG_MAX and errno != 0 and LONG_MIN and errno != 0, or
simply errno != 0.

Posix manpage 'man 3posix strtol' on my system, says also a return value
of 0 could indicate an error if errno != 0 additionally.

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>

int main(int argc, char *argv[])
{
    long int a;
    errno = 0;
    a = strtol(argv[1], NULL, 16);
    if (errno != 0)
        printf("%s\n", strerror(errno));
    printf("%ld\n", a);
    return 0;
}
 
Should print

Numerical result out of range
9223372036854775807

for in input of
999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999

Eric

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Thread

errno "Bill Cunningham" <nospam@nspam.invalid> - 2014-04-26 16:51 -0400
  Re: errno Eric Wolf <eric@boese-wolf.eu> - 2014-04-26 23:11 +0200
    Re: errno "Bill Cunningham" <nospam@nspam.invalid> - 2014-04-26 17:17 -0400
      Re: errno Ike Naar <ike@iceland.freeshell.org> - 2014-04-26 22:35 +0000
        Re: errno "Bill Cunningham" <nospam@nspam.invalid> - 2014-04-26 19:35 -0400
  Re: errno Richard <rgrdev_@gmail.com> - 2014-04-26 23:56 +0200
  Re: errno Barry Schwarz <schwarzb@dqel.com> - 2014-04-26 17:15 -0700
    Re: errno "Bill Cunningham" <nospam@nspam.invalid> - 2014-04-26 20:23 -0400
      Re: errno "Bill Cunningham" <nospam@nspam.invalid> - 2014-04-26 20:27 -0400
    Re: errno "Bill Cunningham" <nospam@nspam.invalid> - 2014-04-26 20:42 -0400

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