x86 64 C data type sizes

[valis]

I am writing some code which is very dependant on the size of the data worked with. I have it written so that size shouldn't matter as long as the return data type is twice as large as one of the parameters.
I was searching google and found a piece on a site that stated int on x86 64 is still only 4 bytes, can anyone verify this?
Also if the above is not true (int is 8), on an x86 64 is a short 32 bits?

Thanks

[kermit]

Various sizes on my machine (AMD Athlon64 chip)

Signed    : Size                    Min                    Max
--------------------------------------------------------------
char      :    1                   -128                    127
short     :    2                 -32768                  32767
int       :    4            -2147483648             2147483647
long      :    8   -9223372036854775808    9223372036854775807
long long :    8   -9223372036854775808    9223372036854775807

Unsigned  : Size                    Min                    Max
--------------------------------------------------------------
char      :    1                      0                    255
short     :    2                      0                  65535
int       :    4                      0             4294967295
long      :    8                      0   18446744073709551615
long long :    8                      0   18446744073709551615

Miscellaneous sizes:
--------------------------------------------------------------
Single precision float:                                      4
Double precision float:                                      8
size_t:                                                      8
ssize_t:                                                     8

Pointers are 8 as well...

And here is the code I used to generate that with:

#include <stdio.h>
#include <limits.h>
#include <unistd.h>             /* For the ssize_t header */

int main(void)
{
    printf("\n\nSigned    : Size %22s %22s\n", "Min", "Max");
    printf
        ("--------------------------------------------------------------\n");
    printf("char      : %4d %22d %22d\n", (int) sizeof(char), CHAR_MIN,
           CHAR_MAX);
    printf("short     : %4d %22d %22d\n", (int) sizeof(short), SHRT_MIN,
           SHRT_MAX);
    printf("int       : %4d %22d %22d\n", (int) sizeof(int), INT_MIN,
           INT_MAX);
    printf("long      : %4d %22ld %22ld\n", (int) sizeof(long), LONG_MIN,
           LONG_MAX);
    printf("long long : %4d %22lld %22lld\n\n", (int) sizeof(long long),
           LLONG_MIN, LLONG_MAX);

    printf("Unsigned  : Size %22s %22s\n", "Min", "Max");
    printf
        ("--------------------------------------------------------------\n");
    printf("char      : %4d %22d %22u\n", (int) sizeof(unsigned char), 0,
           UCHAR_MAX);
    printf("short     : %4d %22d %22u\n", (int) sizeof(unsigned short), 0,
           USHRT_MAX);
    printf("int       : %4d %22d %22u\n", (int) sizeof(unsigned int), 0,
           UINT_MAX);
    printf("long      : %4d %22d %22lu\n", (int) sizeof(unsigned long), 0,
           ULONG_MAX);
    printf("long long : %4d %22d %22llu\n\n",
           (int) sizeof(unsigned long long), 0, ULLONG_MAX);

    printf("Miscellaneous sizes:\n");
    printf
        ("--------------------------------------------------------------\n");

    printf("Single precision float: %38d\n", (int) sizeof(float));
    printf("Double precision float: %38d\n", (int) sizeof(double));
    printf("size_t: %54d\n", (int) sizeof(size_t));
    printf("ssize_t: %53d\n", (int) sizeof(ssize_t));

    return 0;
}

[valis]

Well damn, int is still only 4, much thanks.

[Dave_Sinkula]

Some types may also depend on the OS, not just the platform.
https://cboard.cprogramming.com/showthread.php?p=468408

[valis]

Thanks, that's very good to know, thankfully this app isn't meant for windows.

With cl do you have to use __int64 for a 64 bit data type, or will long long/int do it as well?

[kermit]

Some types may also depend on the OS, not just the platform.
https://cboard.cprogramming.com/showthread.php?p=468408

That is some good reading - thanks for the link Dave.

[CornedBee]

Starting with 7.1, MSC++ supports the long long datatype.