Timespec redefinition error

Question

While executing a Pthread program in C using Visual Studio 2015, I got the following error:

Error C2011 'timespec': 'struct' type redefinition

The following is my code:

#include<pthread.h>
#include<stdlib.h>
#include<stdio.h>


void *calculator(void *parameter);

int main(/*int *argc,char *argv[]*/)
{
    pthread_t thread_obj;
    pthread_attr_t thread_attr;
    char *First_string = "abc"/*argv[1]*/;
    pthread_attr_init(&thread_attr);
        pthread_create(&thread_obj,&thread_attr,calculator,First_string);

}
void *calculator(void *parameter)
{
    int x=atoi((char*)parameter);
    printf("x=%d", x);
}

The pthread.h header file contains the following code related to timespec:

#if !defined(HAVE_STRUCT_TIMESPEC)
#define HAVE_STRUCT_TIMESPEC
#if !defined(_TIMESPEC_DEFINED)
#define _TIMESPEC_DEFINED
struct timespec {
        time_t tv_sec;
        long tv_nsec;
};
#endif /* _TIMESPEC_DEFINED */
#endif /* HAVE_STRUCT_TIMESPEC */

No other header file which I use uses the timespec struct, so there is no chance of redefining. There is no chance of a corrupted header file because it has been downloaded from pthread opensource website.

Answer 1

pthreads-win32 (which I assume you're using) may internally include time.h (time.h is also commonly included by other libraries/headers) - and time.h already declares timespec (also, it does so in a way compatible with pthreads) - yet the pthreads-win32's pthread.h doesn't have the valid include guards for this case (shame on them!). pthreads tries to declare it because it needs it internally, but since it's possible it won't need the entire time.h, it tries to declare only the timespec if possible. Still, you can simply add

#define HAVE_STRUCT_TIMESPEC

before #include <pthread.h> - that will tell the pthreads-win32 header that you already have a proper timespec, and will let your code compile properly.

Alternatively, if you're using pthreads extensively, you may wish to edit the header file itself - simply add that #define HAVE_STRUCT_TIMESPEC to it somewhere near the beginning, and you're good to go.

Further reading: http://mingw-users.1079350.n2.nabble.com/mingw-error-redefinition-of-struct-timespec-td7583722.html