C/C++的size_t类型printf如何打印

Use the z modifier:

size_t x = ...;
ssize_t y = ...;
printf("%zu\n", x);  // prints as unsigned decimal
printf("%zx\n", x);  // prints as hex
printf("%zd\n", y);  // prints as signed decimal

链接：c - How can one print a size_t variable portably using the printf family? - Stack Overflow