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C function "strtoull" failing

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# 8  
What platform are you on...OS/hardware 32 or 64 bits? and insert the statement below into your source...compile it run it and post its output here...
printf("sizeof ULL is %d bytes\n", sizeof(ULL_Type));

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# 9  
I am using 64 bit version of suse.
# uname -m

Output of printf is:
sizeof ULL is 8 bytes

Last edited by rupeshkp728; 10-01-2013 at 02:30 PM..
# 10  
There's something goofy in your program so post it here so others can look at the max value of ULL "18446744073709551615" is way bigger than "5368709120" so im not sure how you are getting wrong results...
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# 11  
This is the program.
I have made small changes to make it look clear
int main(int argc, char *argv[])
    unsigned long long int intValue;

    if(atoi(argv[2]) == 1)
        intValue = strtoull((const char *)argv[1], 0, 10 );
//  ...

    printf("intValue of %s is %llu \n", argv[1], intValue);

    return 0;

Output is
# ./str32_new "5368709120" 1
intValue of 5368709120 is 1073741824

# ./str32_new "536870912" 1
intValue of 536870912 is 536870912

My OS is 64 bit suse.
# 12  
If you had posted a complete yet minimal, compilable program which reproduces the issue, it is likely that this thread would have been resolved long ago.


---------- Post updated at 03:19 PM ---------- Previous update was at 02:54 PM ----------

jim_mcnamara and don_cragun in posts #2 and #4, respectively, correctly deduced from the nature of the numbers involved that a long long was left-truncated into an integer. However, their responses were handicapped by not having access to a complete program.

Had your original post been more forthcoming, either of them would have seen immediately that the truncation was not caused by a printf bug but by incomplete headers.

You need to include the correct headers so that the compiler doesn't default to implicit function prototypes which treat arguments and return values as integers.

What you are seeing is the result of strtoull's return value taken as an integer before assignment to intValue (as if there were a cast operation there). There are surely other bugs just waiting to bite.

Consult the manual pages of each library function to learn which headers must be included.
Also, you should enable compiler warnings; they would have pointed this out to you.


Last edited by alister; 10-01-2013 at 04:25 PM..
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# 13  
I had not included stdlib.h.
Including it resolves the issue.

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