5 files changed, 25 insertions, 5 deletions
diff --git a/src/signal/sigaddset.c b/src/signal/sigaddset.c
index 81b408f3..fae413e1 100644
--- a/src/signal/sigaddset.c
+++ b/src/signal/sigaddset.c
@@ -1,9 +1,14 @@
 #include "sys/types.h"
 #include <signal.h>
+#include "limits.h"
 
 int sigaddset(sigset_t * set, int signo)
 {
-	(void)set; (void)signo;
+	/* TODO: fail with EINVAL if signo is not a valid signal number */
+	size_t byte = signo % CHAR_BIT;
+	int bit = signo / CHAR_BIT;
+
+	set->__bits[byte] |= (1 << bit);
 	return 0;
 }
 /*
diff --git a/src/signal/sigdelset.c b/src/signal/sigdelset.c
index ca20cc43..bcd0d716 100644
--- a/src/signal/sigdelset.c
+++ b/src/signal/sigdelset.c
@@ -1,9 +1,14 @@
 #include "sys/types.h"
 #include <signal.h>
+#include "limits.h"
 
 int sigdelset(sigset_t * set, int signo)
 {
-	(void)set; (void)signo;
+	/* TODO: fail with EINVAL if signo is not a valid signal number */
+	size_t byte = signo % CHAR_BIT;
+	int bit = signo / CHAR_BIT;
+
+	set->__bits[byte] ^= (1 << bit);
 	return 0;
 }
 /*
diff --git a/src/signal/sigemptyset.c b/src/signal/sigemptyset.c
index 2f579579..d09ff500 100644
--- a/src/signal/sigemptyset.c
+++ b/src/signal/sigemptyset.c
@@ -1,9 +1,10 @@
 #include "sys/types.h"
 #include <signal.h>
+#include "string.h"
 
 int sigemptyset(sigset_t * set)
 {
-	(void)set;
+	memset(set, 0, sizeof(*set));
 	return 0;
 }
 /*
diff --git a/src/signal/sigfillset.c b/src/signal/sigfillset.c
index 4530e42a..493912b3 100644
--- a/src/signal/sigfillset.c
+++ b/src/signal/sigfillset.c
@@ -1,9 +1,11 @@
 #include "sys/types.h"
 #include <signal.h>
+#include "string.h"
+#include "limits.h"
 
 int sigfillset(sigset_t * set)
 {
-	(void)set;
+	memset(set, UCHAR_MAX, sizeof(*set));
 	return 0;
 }
 /*
diff --git a/src/signal/sigismember.c b/src/signal/sigismember.c
index 5e21cb5c..6d3c1512 100644
--- a/src/signal/sigismember.c
+++ b/src/signal/sigismember.c
@@ -1,9 +1,16 @@
 #include "sys/types.h"
 #include <signal.h>
+#include "limits.h"
 
 int sigismember(const sigset_t * set, int signo)
 {
-	(void)set; (void)signo;
+	/* TODO: fail with EINVAL if signo is not a valid signal number */
+
+	size_t byte = signo % CHAR_BIT;
+	int bit = signo / CHAR_BIT;
+	if (set->__bits[byte] & (1 << bit)) {
+		return 1;
+	}
 	return 0;
 }
 /*