ssize_t is undefined [duplicate]

Question

In my code I'm using ssize_t but when I try to compile project I got error: unknown type name ‘ssize_t’; did you mean ‘size_t’?

To compile project I'm using cc -std=c11 -O3 I'm including stdint.h and I've also tried stddef.h and others.

Do I have to use some flags or what?

Answer 1

The "signed-size_t" is not part of standard C, instead it's specific to POSIX (Unix, BSD, Linux, etc) and it's in sys/types.h:

https://pubs.opengroup.org/onlinepubs/7908799/xsh/systypes.h.html

On Windows, ssize_t is not defined but SSIZE_T is - but I assume you're on a POSIX system.