Since I can never remember the width for each suffix, I am just reprinting them here from https://en.wikibooks.org/wiki/X86_Assembly/GAS_Syntax

GAS assembly instructions are generally suffixed with the letters “b”, “s”, “w”, “l”, “q” or “t” to determine what size operand is being manipulated.

b = byte (8 bit)
s = short (16 bit integer) or single (32-bit floating point)
w = word (16 bit)
l = long (32 bit integer or 64-bit floating point)
q = quad (64 bit)
t = ten bytes (80-bit floating point)

If the suffix is not specified, and there are no memory operands for the instruction, GAS infers the operand size from the size of the destination register operand (the final operand).

Being one level higher than assembly, C has different data size (on x86-64):

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#include <stdio.h>
int main(int argc, char *argv[])
{
    printf("char    is %zu\n", sizeof(char));
    printf("short   is %zu\n", sizeof(short));
    printf("int     is %zu\n", sizeof(int));
    printf("long    is %zu\n", sizeof(long));
    printf("size_t  is %zu\n", sizeof(size_t));
    return 0;
}
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char    is 1
short   is 2
int     is 4
long    is 8
size_t  is 8