Search code examples
cstructcompiler-flags

struct accessible without declaration?

I have the following Code

#ifdef ENV_TI
typedef struct timespecT
{
    Uint32 tv_sec;
    Uint32 tv_nsec; 
}timespec;
#endif
#ifndef ENV_TI
struct timespec currentTime; // This Line
#else 
timespec currentTime;
#endif

How is the currentTime accessible if i have NOT defined ENV_TI flag and the timespec is defined under the ENV_TI flag?

I am running this code on Linux, gcc compiler.

Solution

  • struct timespec is a type name used in e.g. Linux, see the manual page for clock_gettime(). You get the type declaration by doing #include <time.h> on systems that support it. According to the manual page, this is POSIX standard functionality.

    I think the code you're looking at is using the #ifdef to declare the type for environments that don't support it natively.