Please find attached a short test programme derived from the semaphore
handling code in Poco. The test crashes in the call to semget(),
reporting 'Bad system call (core dumped)'. I am using the latest 32-bit
snapshot (2013-06-08).
The test programme runs correctly under Fedora 18 x64.
BTW, the man page for ftok(3) states that the second parameter
('proj_id') must be non-zero. Contrary to this, Poco uses zero for
'proj_id'. This is easy enough to patch, but does anyone know the effect
of using zero here? If there's no good reason for it then I'll raise a
ticket with Poco and get it changed.
Many thanks in advance for looking at this problem,
Dave.
/* Compile: gcc -o poco_ne poco_ne.c
*/
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
/* Error handling. */
void FatalError(const char* const pmsg)
{
fprintf(stderr, "%s\n", pmsg);
exit(1);
}
int main()
{
/* Create a file. */
const char* const pfilename = "try.txt";
int fd = open(pfilename, O_WRONLY | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
if (fd == -1)
FatalError("open() failed.");
close(fd);
/* Generate a key, using the file we just created. */
key_t key = ftok(pfilename, 'a');
if (key == -1)
FatalError("ftok() failed.");
/* Get the semaphore set identifier */
fprintf(stderr, "Trying semget()\n");
fprintf(stderr, "This causes 'Bad system call (core dumped)' in Cygwin.\n");
int semid = semget(key, 1, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH | IPC_CREAT | IPC_EXCL);
fprintf(stderr, "OK - that worked. semget() returned %i\n", semid);
return 0;
}
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