redefinition of 'struct timeval' in several headers

Question

I have several issues to compile a C program to stream sound from Intel Edison to devices (iOS and Android).

I made a C program : I use alsa/asoundlib.h and pthread.h in my program I don't include sys/time.h because ALSA does not allow this.

I use lot of timeval in my program, when i compile it on my computer i'ts compile fine, but on my edison when I :

gcc -std=c99 -Wall -O0 -ggdb -o sender sender.c spsc_circular_queue.c -lopus -lasound -lpthread


In file included from /usr/include/alsa/asoundlib.h:49:0,
                 from sender.c:16:
/usr/include/alsa/global.h:145:8: error: redefinition of 'struct timespec'
 struct timespec {
        ^
In file included from /usr/include/alsa/global.h:34:0,
                 from /usr/include/alsa/asoundlib.h:49,
                 from sender.c:16:
/usr/include/time.h:120:8: note: originally defined here
 struct timespec
        ^
In file included from /usr/include/time.h:41:0,
                 from /usr/include/sched.h:34,
                 from sender.c:18:
/usr/include/bits/time.h:30:8: error: redefinition of 'struct timeval'
 struct timeval
        ^
In file included from /usr/include/alsa/asoundlib.h:49:0,
                 from sender.c:16:
/usr/include/alsa/global.h:140:8: note: originally defined here
 struct timeval {
        ^
Makefile:16: recipe for target 'sender' failed
make: *** [sender] Error 1

How can I manage to stop these redifinitions ?! Thank you for your help !

Extra info:

I include :

#include <assert.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
#include <alloca.h>
#include <limits.h>
#include <inttypes.h>
#include <alsa/asoundlib.h>
#include "../opus/include/opus.h"
#include <pthread.h>
#include "spsc_circular_queue.h"

I remove sched.h, nothing happen

You included `/usr/include/sched.h` in sender.c on line 18, which includes `/usr/include/time.h`. — mch, Apr 06 '17 at 13:00
You did `#include `, which does `#include `. That's the problem. If you remove `#include `, the error message will change to lead you to the next problem. — mch, Apr 06 '17 at 13:10
@mch It is reasonable to expect system headers, including `time.h`, to have proper multiple-inclusion guards. Indeed GLIBC's `time.h` has such. The problem is not with `time.h` being included from multiple locations. — John Bollinger, Apr 06 '17 at 13:33

John Bollinger · Accepted Answer · 2017-04-06T13:40:04.733

ALSA depends on types struct timespec and struct timeval. Its global.h header therefore appropriately does this:

/* for timeval and timespec */
#include <time.h>

However, it seems to be of the opinion that GLIBC defines those structures only when an appropriate feature-test macro has been defined, for that header also says:

#ifdef __GLIBC__
#if !defined(_POSIX_C_SOURCE) && !defined(_POSIX_SOURCE)
struct timeval {
  time_t      tv_sec;     /* seconds */
  long        tv_usec;    /* microseconds */
};

struct timespec {
  time_t      tv_sec;     /* seconds */
  long        tv_nsec;    /* nanoseconds */
};
#endif
#endif

It's hard to determine under what circumstances GLIBC actually does declare the wanted structures. It indeed does do so conditionally, but it appears that the conditions, at least in GLIBC v2.17, are more general than ALSA assumes. Thus ALSA seems to have fallen out of sync with GLIBC, if indeed it ever was perfectly synchronized in the first place, and under some conditions it produces the duplicate declaration problem you encountered.

Your best bet is probably to define the _POSIX_C_SOURCE macro when you compile. The values supported by GLIBC are documented on the linked manual page. Any value, except possibly 0, ought to solve the problem for you, but the effects will be broader, so you may need to experiment with different values. To start, I suggest the value 200809L, which is the most inclusive among the values supported by GLIBC:

gcc -D_POSIX_C_SOURCE=200809L -std=c99 -Wall -O0 -ggdb -o sender sender.c spsc_circular_queue.c -lopus -lasound -lpthread

ALSA should then rely on the system's definitions instead of issuing its own, duplicate ones.

Woww ! Thank you ! I will work on it to understand better, my program compile ! — maathor, Apr 06 '17 at 13:44
Unfortunately this doesn't work at least for me - you then get some errors about `it_interval` and `it_value` having incomplete types in `time.h`. — Timmmm, Jun 03 '17 at 16:13

redefinition of 'struct timeval' in several headers

1 Answers1