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-rw-r--r--lib/maxfd.c26
1 files changed, 26 insertions, 0 deletions
diff --git a/lib/maxfd.c b/lib/maxfd.c
new file mode 100644
index 0000000..dcd4d3d
--- /dev/null
+++ b/lib/maxfd.c
@@ -0,0 +1,26 @@
1#include "./maxfd.h"
2#include <errno.h>
3
4long open_max (void) {
5 long maxfd = 0L;
6 /* Try sysconf(_SC_OPEN_MAX) first, as it can be higher than OPEN_MAX.
7 * If that fails and the macro isn't defined, we fall back to an educated
8 * guess. There's no guarantee that our guess is adequate and the program
9 * will die with SIGSEGV if it isn't and the upper boundary is breached. */
10
11#ifdef _SC_OPEN_MAX
12 errno = 0;
13 if ((maxfd = sysconf (_SC_OPEN_MAX)) < 0) {
14 if (errno == 0)
15 maxfd = DEFAULT_MAXFD; /* it's indeterminate */
16 else
17 die (STATE_UNKNOWN, _("sysconf error for _SC_OPEN_MAX\n"));
18 }
19#elif defined(OPEN_MAX)
20 return OPEN_MAX
21#else /* sysconf macro unavailable, so guess (may be wildly inaccurate) */
22 return DEFAULT_MAXFD;
23#endif
24
25 return(maxfd);
26}