diff --git a/lib/rfcnb/session.c b/lib/rfcnb/session.c
index e1ee2b580a1..53e566da520 100644
--- a/lib/rfcnb/session.c
+++ b/lib/rfcnb/session.c
@@ -295,9 +295,7 @@ RFCNB_Hangup(struct RFCNB_Con *con_Handle)
 int
 RFCNB_Set_Sock_NoDelay(struct RFCNB_Con *con_Handle, BOOL yn)
 {
-
-    return (setsockopt(con_Handle->fd, IPPROTO_TCP, TCP_NODELAY,
-                       (char *) &yn, sizeof(yn)));
+    return setsockopt(con_Handle->fd, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&yn), sizeof(yn));
 }
 
 #if NOT_IMPLEMENTED
diff --git a/src/WinSvc.cc b/src/WinSvc.cc
index 670784a8819..b2c51749b19 100644
--- a/src/WinSvc.cc
+++ b/src/WinSvc.cc
@@ -965,7 +965,7 @@ static int Win32SockInit(void)
         } else {
             opt = opt | SO_SYNCHRONOUS_NONALERT;
 
-            if (::setsockopt(INVALID_SOCKET, SOL_SOCKET, SO_OPENTYPE, (char *) &opt, optlen)) {
+            if (::setsockopt(INVALID_SOCKET, SOL_SOCKET, SO_OPENTYPE, reinterpret_cast<char *>(&opt), optlen)) {
                 s_iInitCount = -3;
                 WSACleanup();
                 return (s_iInitCount);
diff --git a/src/client_side.cc b/src/client_side.cc
index 3d6f0a5727e..d2dfdcd1d4c 100644
--- a/src/client_side.cc
+++ b/src/client_side.cc
@@ -2198,7 +2198,7 @@ ConnStateData::start()
             (transparent() || port->disable_pmtu_discovery == DISABLE_PMTU_ALWAYS)) {
 #if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
         int i = IP_PMTUDISC_DONT;
-        if (setsockopt(clientConnection->fd, SOL_IP, IP_MTU_DISCOVER, &i, sizeof(i)) < 0) {
+        if (setsockopt(clientConnection->fd, SOL_IP, IP_MTU_DISCOVER, reinterpret_cast<char *>(&i), sizeof(i)) < 0) {
             int xerrno = errno;
             debugs(33, 2, "WARNING: Path MTU discovery disabling failed on " << clientConnection << " : " << xstrerr(xerrno));
         }
diff --git a/src/clients/FtpGateway.cc b/src/clients/FtpGateway.cc
index c3c7b21d072..1d98e4439ab 100644
--- a/src/clients/FtpGateway.cc
+++ b/src/clients/FtpGateway.cc
@@ -1772,8 +1772,7 @@ ftpOpenListenSocket(Ftp::Gateway * ftpState, int fallback)
     if (fallback) {
         int on = 1;
         errno = 0;
-        if (setsockopt(ftpState->ctrl.conn->fd, SOL_SOCKET, SO_REUSEADDR,
-                       (char *) &on, sizeof(on)) == -1) {
+        if (setsockopt(ftpState->ctrl.conn->fd, SOL_SOCKET, SO_REUSEADDR, reinterpret_cast<char *>(&on), sizeof(on)) == -1) {
             int xerrno = errno;
             // SO_REUSEADDR is only an optimization, no need to be verbose about error
             debugs(9, 4, "setsockopt failed: " << xstrerr(xerrno));
diff --git a/src/comm.cc b/src/comm.cc
index f703786d157..4dc981896c8 100644
--- a/src/comm.cc
+++ b/src/comm.cc
@@ -210,7 +210,7 @@ commSetBindAddressNoPort(const int fd)
 {
 #if defined(IP_BIND_ADDRESS_NO_PORT)
     int flag = 1;
-    if (setsockopt(fd, IPPROTO_IP, IP_BIND_ADDRESS_NO_PORT, reinterpret_cast<char*>(&flag), sizeof(flag)) < 0) {
+    if (setsockopt(fd, IPPROTO_IP, IP_BIND_ADDRESS_NO_PORT, reinterpret_cast<char *>(&flag), sizeof(flag)) < 0) {
         const auto savedErrno = errno;
         debugs(50, DBG_IMPORTANT, "ERROR: setsockopt(IP_BIND_ADDRESS_NO_PORT) failure: " << xstrerr(savedErrno));
     }
@@ -293,7 +293,7 @@ static void
 comm_set_v6only(int fd, int tos)
 {
 #ifdef IPV6_V6ONLY
-    if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, (char *) &tos, sizeof(int)) < 0) {
+    if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, reinterpret_cast<char *>(&tos), sizeof(tos)) < 0) {
         int xerrno = errno;
         debugs(50, DBG_IMPORTANT, MYNAME << "setsockopt(IPV6_V6ONLY) " << (tos?"ON":"OFF") << " for FD " << fd << ": " << xstrerr(xerrno));
     }
@@ -335,7 +335,7 @@ comm_set_transparent(int fd)
 
 #if defined(soLevel) && defined(soFlag)
     int tos = 1;
-    if (setsockopt(fd, soLevel, soFlag, (char *) &tos, sizeof(int)) < 0) {
+    if (setsockopt(fd, soLevel, soFlag, reinterpret_cast<char *>(&tos), sizeof(tos)) < 0) {
         int xerrno = errno;
         debugs(50, DBG_IMPORTANT, MYNAME << "setsockopt(TPROXY) on FD " << fd << ": " << xstrerr(xerrno));
     } else {
@@ -499,7 +499,7 @@ comm_apply_flags(int new_socket,
 #if defined(SO_REUSEPORT)
         if (flags & COMM_REUSEPORT) {
             int on = 1;
-            if (setsockopt(new_socket, SOL_SOCKET, SO_REUSEPORT, reinterpret_cast<char*>(&on), sizeof(on)) < 0) {
+            if (setsockopt(new_socket, SOL_SOCKET, SO_REUSEPORT, reinterpret_cast<char *>(&on), sizeof(on)) < 0) {
                 const auto savedErrno = errno;
                 const auto errorMessage = ToSBuf("cannot enable SO_REUSEPORT socket option when binding to ",
                                                  addr, ": ", xstrerr(savedErrno));
@@ -788,7 +788,7 @@ comm_reset_close(const Comm::ConnectionPointer &conn)
     L.l_onoff = 1;
     L.l_linger = 0;
 
-    if (setsockopt(conn->fd, SOL_SOCKET, SO_LINGER, (char *) &L, sizeof(L)) < 0) {
+    if (setsockopt(conn->fd, SOL_SOCKET, SO_LINGER, reinterpret_cast<char *>(&L), sizeof(L)) < 0) {
         int xerrno = errno;
         debugs(50, DBG_CRITICAL, "ERROR: Closing " << conn << " with TCP RST: " << xstrerr(xerrno));
     }
@@ -803,7 +803,7 @@ old_comm_reset_close(int fd)
     L.l_onoff = 1;
     L.l_linger = 0;
 
-    if (setsockopt(fd, SOL_SOCKET, SO_LINGER, (char *) &L, sizeof(L)) < 0) {
+    if (setsockopt(fd, SOL_SOCKET, SO_LINGER, reinterpret_cast<char *>(&L), sizeof(L)) < 0) {
         int xerrno = errno;
         debugs(50, DBG_CRITICAL, "ERROR: Closing FD " << fd << " with TCP RST: " << xstrerr(xerrno));
     }
@@ -1026,7 +1026,7 @@ commSetNoLinger(int fd)
     L.l_onoff = 0;      /* off */
     L.l_linger = 0;
 
-    if (setsockopt(fd, SOL_SOCKET, SO_LINGER, (char *) &L, sizeof(L)) < 0) {
+    if (setsockopt(fd, SOL_SOCKET, SO_LINGER, reinterpret_cast<char *>(&L), sizeof(L)) < 0) {
         int xerrno = errno;
         debugs(50, DBG_CRITICAL, MYNAME << "FD " << fd << ": " << xstrerr(xerrno));
     }
@@ -1037,7 +1037,7 @@ static void
 commSetReuseAddr(int fd)
 {
     int on = 1;
-    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, (char *) &on, sizeof(on)) < 0) {
+    if (setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, reinterpret_cast<char *>(&on), sizeof(on)) < 0) {
         int xerrno = errno;
         debugs(50, DBG_IMPORTANT, MYNAME << "FD " << fd << ": " << xstrerr(xerrno));
     }
@@ -1046,16 +1046,16 @@ commSetReuseAddr(int fd)
 static void
 commSetTcpRcvbuf(int fd, int size)
 {
-    if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *) &size, sizeof(size)) < 0) {
+    if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, reinterpret_cast<char *>(&size), sizeof(size)) < 0) {
         int xerrno = errno;
         debugs(50, DBG_IMPORTANT, MYNAME << "FD " << fd << ", SIZE " << size << ": " << xstrerr(xerrno));
     }
-    if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, (char *) &size, sizeof(size)) < 0) {
+    if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, reinterpret_cast<char *>(&size), sizeof(size)) < 0) {
         int xerrno = errno;
         debugs(50, DBG_IMPORTANT, MYNAME << "FD " << fd << ", SIZE " << size << ": " << xstrerr(xerrno));
     }
 #ifdef TCP_WINDOW_CLAMP
-    if (setsockopt(fd, SOL_TCP, TCP_WINDOW_CLAMP, (char *) &size, sizeof(size)) < 0) {
+    if (setsockopt(fd, SOL_TCP, TCP_WINDOW_CLAMP, reinterpret_cast<char *>(&size), sizeof(size)) < 0) {
         int xerrno = errno;
         debugs(50, DBG_IMPORTANT, MYNAME << "FD " << fd << ", SIZE " << size << ": " << xstrerr(xerrno));
     }
@@ -1151,8 +1151,7 @@ static void
 commSetTcpNoDelay(int fd)
 {
     int on = 1;
-
-    if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, (char *) &on, sizeof(on)) < 0) {
+    if (setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&on), sizeof(on)) < 0) {
         int xerrno = errno;
         debugs(50, DBG_IMPORTANT, MYNAME << "FD " << fd << ": " << xstrerr(xerrno));
     }
diff --git a/src/comm/Tcp.cc b/src/comm/Tcp.cc
index 43c5da0d9ef..7c47aceb62c 100644
--- a/src/comm/Tcp.cc
+++ b/src/comm/Tcp.cc
@@ -30,7 +30,7 @@ SetSocketOption(const int fd, const int level, const int optName, const Option &
 {
     static_assert(std::is_trivially_copyable<Option>::value, "setsockopt() expects POD-like options");
     static_assert(!std::is_same<Option, bool>::value, "setsockopt() uses int to represent boolean options");
-    if (setsockopt(fd, level, optName, &optValue, sizeof(optValue)) < 0) {
+    if (setsockopt(fd, level, optName, reinterpret_cast<char *>(const_cast<Option *>(&optValue)), sizeof(optValue)) < 0) {
         const auto xerrno = errno;
         debugs(5, DBG_IMPORTANT, "ERROR: setsockopt(2) failure: " << xstrerr(xerrno));
         // TODO: Generalize to throw on errors when some callers need that.
diff --git a/src/comm/TcpAcceptor.cc b/src/comm/TcpAcceptor.cc
index dcc52fbaa1b..f6ae5bdab35 100644
--- a/src/comm/TcpAcceptor.cc
+++ b/src/comm/TcpAcceptor.cc
@@ -163,7 +163,7 @@ Comm::TcpAcceptor::setListen()
         bzero(&afa, sizeof(afa));
         debugs(5, DBG_IMPORTANT, "Installing accept filter '" << Config.accept_filter << "' on " << conn);
         xstrncpy(afa.af_name, Config.accept_filter, sizeof(afa.af_name));
-        if (setsockopt(conn->fd, SOL_SOCKET, SO_ACCEPTFILTER, &afa, sizeof(afa)) < 0) {
+        if (setsockopt(conn->fd, SOL_SOCKET, SO_ACCEPTFILTER, reinterpret_cast<char *>(&afa), sizeof(afa)) < 0) {
             int xerrno = errno;
             debugs(5, DBG_CRITICAL, "WARNING: SO_ACCEPTFILTER '" << Config.accept_filter << "': '" << xstrerr(xerrno));
         }
@@ -171,7 +171,7 @@ Comm::TcpAcceptor::setListen()
         int seconds = 30;
         if (strncmp(Config.accept_filter, "data=", 5) == 0)
             seconds = atoi(Config.accept_filter + 5);
-        if (setsockopt(conn->fd, IPPROTO_TCP, TCP_DEFER_ACCEPT, &seconds, sizeof(seconds)) < 0) {
+        if (setsockopt(conn->fd, IPPROTO_TCP, TCP_DEFER_ACCEPT, reinterpret_cast<char *>(&seconds), sizeof(seconds)) < 0) {
             int xerrno = errno;
             debugs(5, DBG_CRITICAL, "WARNING: TCP_DEFER_ACCEPT '" << Config.accept_filter << "': '" << xstrerr(xerrno));
         }
diff --git a/src/ip/Intercept.cc b/src/ip/Intercept.cc
index 689d9eef669..762b56c167f 100644
--- a/src/ip/Intercept.cc
+++ b/src/ip/Intercept.cc
@@ -429,7 +429,7 @@ Ip::Intercept::ProbeForTproxy(Ip::Address &test)
         tmp.getSockAddr(tmp_ip6);
 
         if ( (tmp_sock = socket(PF_INET6, SOCK_STREAM, IPPROTO_TCP)) >= 0 &&
-                setsockopt(tmp_sock, soLevel, soFlag, (char *)&tos, sizeof(int)) == 0 &&
+                setsockopt(tmp_sock, soLevel, soFlag, reinterpret_cast<char *>(&tos), sizeof(tos)) == 0 &&
                 bind(tmp_sock, (struct sockaddr*)&tmp_ip6, sizeof(struct sockaddr_in6)) == 0 ) {
 
             debugs(3, 3, "IPv6 TPROXY support detected. Using.");
@@ -461,7 +461,7 @@ Ip::Intercept::ProbeForTproxy(Ip::Address &test)
         tmp.getSockAddr(tmp_ip4);
 
         if ( (tmp_sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP)) >= 0 &&
-                setsockopt(tmp_sock, soLevel, soFlag, (char *)&tos, sizeof(int)) == 0 &&
+                setsockopt(tmp_sock, soLevel, soFlag, reinterpret_cast<char *>(&tos), sizeof(tos)) == 0 &&
                 bind(tmp_sock, (struct sockaddr*)&tmp_ip4, sizeof(struct sockaddr_in)) == 0 ) {
 
             debugs(3, 3, "IPv4 TPROXY support detected. Using.");
diff --git a/src/ip/QosConfig.cc b/src/ip/QosConfig.cc
index 2e4b2564744..b7a10b82d5c 100644
--- a/src/ip/QosConfig.cc
+++ b/src/ip/QosConfig.cc
@@ -45,9 +45,8 @@ Ip::Qos::getTosFromServer(const Comm::ConnectionPointer &server, fde *clientFde)
 #if USE_QOS_TOS && _SQUID_LINUX_
     /* Bug 2537: This part of ZPH only applies to patched Linux kernels. */
     tos_t tos = 1;
-    int tos_len = sizeof(tos);
     clientFde->tosFromServer = 0;
-    if (setsockopt(server->fd,SOL_IP,IP_RECVTOS,&tos,tos_len)==0) {
+    if (setsockopt(server->fd, SOL_IP, IP_RECVTOS, reinterpret_cast<char *>(&tos), sizeof(tos)) == 0) {
         unsigned char buf[512];
         int len = 512;
         if (getsockopt(server->fd,SOL_IP,IP_PKTOPTIONS,buf,(socklen_t*)&len) == 0) {
@@ -531,15 +530,13 @@ Ip::Qos::setSockTos(const int fd, tos_t tos, int type)
 {
     // Bug 3731: FreeBSD produces 'invalid option'
     // unless we pass it a 32-bit variable storing 8-bits of data.
-    // NP: it is documented as 'int' for all systems, even those like Linux which accept 8-bit char
-    //     so we convert to a int before setting.
     int bTos = tos;
 
     debugs(50, 3, "for FD " << fd << " to " << bTos);
 
     if (type == AF_INET) {
 #if defined(IP_TOS)
-        const int x = setsockopt(fd, IPPROTO_IP, IP_TOS, &bTos, sizeof(bTos));
+        const int x = setsockopt(fd, IPPROTO_IP, IP_TOS, reinterpret_cast<char *>(&bTos), sizeof(bTos));
         if (x < 0) {
             int xerrno = errno;
             debugs(50, 2, "setsockopt(IP_TOS) on " << fd << ": " << xstrerr(xerrno));
@@ -551,7 +548,7 @@ Ip::Qos::setSockTos(const int fd, tos_t tos, int type)
 #endif
     } else { // type == AF_INET6
 #if defined(IPV6_TCLASS)
-        const int x = setsockopt(fd, IPPROTO_IPV6, IPV6_TCLASS, &bTos, sizeof(bTos));
+        const int x = setsockopt(fd, IPPROTO_IPV6, IPV6_TCLASS, reinterpret_cast<char *>(&bTos), sizeof(bTos));
         if (x < 0) {
             int xerrno = errno;
             debugs(50, 2, "setsockopt(IPV6_TCLASS) on " << fd << ": " << xstrerr(xerrno));
@@ -579,7 +576,7 @@ Ip::Qos::setSockNfmark(const int fd, nfmark_t mark)
 {
 #if SO_MARK && USE_LIBCAP
     debugs(50, 3, "for FD " << fd << " to " << mark);
-    const int x = setsockopt(fd, SOL_SOCKET, SO_MARK, &mark, sizeof(nfmark_t));
+    const int x = setsockopt(fd, SOL_SOCKET, SO_MARK, reinterpret_cast<char *>(&mark), sizeof(mark));
     if (x < 0) {
         int xerrno = errno;
         debugs(50, 2, "setsockopt(SO_MARK) on " << fd << ": " << xstrerr(xerrno));
diff --git a/src/ip/tools.cc b/src/ip/tools.cc
index 0697221b5e0..17e6a5110b2 100644
--- a/src/ip/tools.cc
+++ b/src/ip/tools.cc
@@ -43,7 +43,7 @@ Ip::ProbeTransport()
     // (AKA. the operating system supports RFC 3493 section 5.3)
 #if defined(IPV6_V6ONLY)
     int tos = 0;
-    if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, (char *) &tos, sizeof(int)) == 0) {
+    if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, reinterpret_cast<char *>(&tos), sizeof(tos)) == 0) {
         debugs(3, 2, "Detected IPv6 hybrid or v4-mapping stack...");
         EnableIpv6 |= IPV6_SPECIAL_V4MAPPING;
     } else {
diff --git a/src/ipc.cc b/src/ipc.cc
index 40d34b4755a..781831ad0af 100644
--- a/src/ipc.cc
+++ b/src/ipc.cc
@@ -159,22 +159,22 @@ ipcCreate(int type, const char *prog, const char *const args[], const char *name
         }
 
         errno = 0;
-        if (setsockopt(fds[0], SOL_SOCKET, SO_SNDBUF, (void *) &buflen, sizeof(buflen)) == -1)  {
+        if (setsockopt(fds[0], SOL_SOCKET, SO_SNDBUF, reinterpret_cast<char *>(&buflen), sizeof(buflen)) == -1)  {
             xerrno = errno;
             debugs(54, DBG_IMPORTANT, "ERROR: setsockopt failed: " << xstrerr(xerrno));
             errno = 0;
         }
-        if (setsockopt(fds[0], SOL_SOCKET, SO_RCVBUF, (void *) &buflen, sizeof(buflen)) == -1) {
+        if (setsockopt(fds[0], SOL_SOCKET, SO_RCVBUF, reinterpret_cast<char *>(&buflen), sizeof(buflen)) == -1) {
             xerrno = errno;
             debugs(54, DBG_IMPORTANT, "ERROR: setsockopt failed: " << xstrerr(xerrno));
             errno = 0;
         }
-        if (setsockopt(fds[1], SOL_SOCKET, SO_SNDBUF, (void *) &buflen, sizeof(buflen)) == -1) {
+        if (setsockopt(fds[1], SOL_SOCKET, SO_SNDBUF, reinterpret_cast<char *>(&buflen), sizeof(buflen)) == -1) {
             xerrno = errno;
             debugs(54, DBG_IMPORTANT, "ERROR: setsockopt failed: " << xstrerr(xerrno));
             errno = 0;
         }
-        if (setsockopt(fds[1], SOL_SOCKET, SO_RCVBUF, (void *) &buflen, sizeof(buflen)) == -1) {
+        if (setsockopt(fds[1], SOL_SOCKET, SO_RCVBUF, reinterpret_cast<char *>(&buflen), sizeof(buflen)) == -1) {
             xerrno = errno;
             debugs(54, DBG_IMPORTANT, "ERROR: setsockopt failed: " << xstrerr(xerrno));
             errno = 0;
diff --git a/src/ipc_win32.cc b/src/ipc_win32.cc
index f7416288b14..2833d6bd37b 100644
--- a/src/ipc_win32.cc
+++ b/src/ipc_win32.cc
@@ -126,7 +126,7 @@ ipcCreate(int type, const char *prog, const char *const args[], const char *name
     if (WIN32_OS_version != _WIN_OS_WINNT) {
         getsockopt(INVALID_SOCKET, SOL_SOCKET, SO_OPENTYPE, (char *) &opt, &optlen);
         opt = opt & ~(SO_SYNCHRONOUS_NONALERT | SO_SYNCHRONOUS_ALERT);
-        setsockopt(INVALID_SOCKET, SOL_SOCKET, SO_OPENTYPE, (char *) &opt, sizeof(opt));
+        setsockopt(INVALID_SOCKET, SOL_SOCKET, SO_OPENTYPE, reinterpret_cast<char *>(&opt), sizeof(opt));
     }
 
     if (type == IPC_TCP_SOCKET) {
@@ -166,7 +166,7 @@ ipcCreate(int type, const char *prog, const char *const args[], const char *name
     if (WIN32_OS_version != _WIN_OS_WINNT) {
         getsockopt(INVALID_SOCKET, SOL_SOCKET, SO_OPENTYPE, (char *) &opt, &optlen);
         opt = opt | SO_SYNCHRONOUS_NONALERT;
-        setsockopt(INVALID_SOCKET, SOL_SOCKET, SO_OPENTYPE, (char *) &opt, optlen);
+        setsockopt(INVALID_SOCKET, SOL_SOCKET, SO_OPENTYPE, reinterpret_cast<char *>(&opt), optlen);
     }
 
     if (crfd < 0) {
diff --git a/src/multicast.cc b/src/multicast.cc
index c182867c3cd..5b3cb5f854e 100644
--- a/src/multicast.cc
+++ b/src/multicast.cc
@@ -22,7 +22,7 @@ mcastSetTtl(int fd, int mcast_ttl)
 #ifdef IP_MULTICAST_TTL
     char ttl = (char) mcast_ttl;
 
-    if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, 1) < 0) {
+    if (setsockopt(fd, IPPROTO_IP, IP_MULTICAST_TTL, reinterpret_cast<char *>(&ttl), sizeof(ttl)) < 0) {
         int xerrno = errno;
         debugs(50, DBG_IMPORTANT, "mcastSetTtl: FD " << fd << ", TTL: " << mcast_ttl << ": " << xstrerr(xerrno));
     }
@@ -54,11 +54,11 @@ mcastJoinGroups(const ipcache_addrs *ia, const Dns::LookupDetails &, void *)
 
         mr.imr_interface.s_addr = INADDR_ANY;
 
-        if (setsockopt(icpIncomingConn->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *) &mr, sizeof(struct ip_mreq)) < 0)
+        if (setsockopt(icpIncomingConn->fd, IPPROTO_IP, IP_ADD_MEMBERSHIP, reinterpret_cast<char *>(&mr), sizeof(mr)) < 0)
             debugs(7, DBG_IMPORTANT, "ERROR: Join failed for " << icpIncomingConn << ", Multicast IP=" << ip);
 
         char c = 0;
-        if (setsockopt(icpIncomingConn->fd, IPPROTO_IP, IP_MULTICAST_LOOP, &c, 1) < 0) {
+        if (setsockopt(icpIncomingConn->fd, IPPROTO_IP, IP_MULTICAST_LOOP, reinterpret_cast<char *>(&c), sizeof(c)) < 0) {
             int xerrno = errno;
             debugs(7, DBG_IMPORTANT, "ERROR: " << icpIncomingConn << " can't disable multicast loopback: " << xstrerr(xerrno));
         }
diff --git a/src/wccp2.cc b/src/wccp2.cc
index d46a5f82647..63e8974aa50 100644
--- a/src/wccp2.cc
+++ b/src/wccp2.cc
@@ -983,7 +983,7 @@ wccp2ConnectionOpen(void)
 #if defined(IP_MTU_DISCOVER) && defined(IP_PMTUDISC_DONT)
     {
         int i = IP_PMTUDISC_DONT;
-        if (setsockopt(theWccp2Connection, SOL_IP, IP_MTU_DISCOVER, &i, sizeof i) < 0) {
+        if (setsockopt(theWccp2Connection, SOL_IP, IP_MTU_DISCOVER, reinterpret_cast<char *>(&i), sizeof(i)) < 0) {
             int xerrno = errno;
             debugs(80, 2, "WARNING: Path MTU discovery could not be disabled on FD " << theWccp2Connection << ": " << xstrerr(xerrno));
         }
diff --git a/tools/purge/socket.cc b/tools/purge/socket.cc
index c09bb9d33bd..3dfa690bbb8 100644
--- a/tools/purge/socket.cc
+++ b/tools/purge/socket.cc
@@ -70,14 +70,12 @@ setSocketBuffers( int sockfd, int size )
 // returns: -1 on setsockopt() errors, 0 otherwise
 // warning: prints error message on stderr, errno will be changed
 {
-    if ( setsockopt( sockfd, SOL_SOCKET, SO_RCVBUF,
-                     (char*) &size, sizeof(size) ) == -1 ) {
+    if (setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, reinterpret_cast<char *>(&size), sizeof(size)) == -1) {
         perror( "setsockopt( SO_RCVBUF )" );
         return -1;
     }
 
-    if ( setsockopt( sockfd, SOL_SOCKET, SO_SNDBUF,
-                     (char*) &size, sizeof(size) ) == -1 ) {
+    if (setsockopt(sockfd, SOL_SOCKET, SO_SNDBUF, reinterpret_cast<char *>(&size), sizeof(size)) == -1) {
         perror( "setsockopt( SO_SNDBUF )" );
         return -1;
     }
@@ -111,9 +109,8 @@ setSocketNoDelay( int sockfd, bool)
 // returns: 0, if everything worked out o.k.
 //         -1, if an error occurred (e.g. datagram socket)
 {
-    const int delay = 1;
-    if ( setsockopt( sockfd, IPPROTO_TCP, TCP_NODELAY,
-                     (const char*) &delay, sizeof(delay) ) == -1 ) {
+    int delay = 1;
+    if (setsockopt(sockfd, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&delay), sizeof(delay)) == -1) {
         perror( "setsockopt( TCP_NODELAY ) failed" );
         return -1;
     } else
@@ -133,9 +130,8 @@ commonCode(int &sockfd, bool nodelay, int sendBufferSize, int recvBufferSize)
     // set TCP_NODELAY option, if that is wanted.
     // The socket API default is unset.
     if ( nodelay ) {
-        const int delay = 1;
-        if ( setsockopt( sockfd, IPPROTO_TCP, TCP_NODELAY,
-                         (const char*) &delay, sizeof(delay) ) == -1 ) {
+        int delay = 1;
+        if (setsockopt(sockfd, IPPROTO_TCP, TCP_NODELAY, reinterpret_cast<char *>(&delay), sizeof(delay)) == -1) {
             perror( "setsockopt( TCP_NODELAY ) failed" );
             close(sockfd);
             return -1;
@@ -144,8 +140,7 @@ commonCode(int &sockfd, bool nodelay, int sendBufferSize, int recvBufferSize)
 
     // set the socket send buffer size explicitly, or use the system default
     if ( sendBufferSize >= 0 ) {
-        if ( setsockopt( sockfd, SOL_SOCKET, SO_SNDBUF, (char*) &sendBufferSize,
-                         sizeof(sendBufferSize) ) == -1 ) {
+        if (setsockopt(sockfd, SOL_SOCKET, SO_SNDBUF, reinterpret_cast<char *>(&sendBufferSize), sizeof(sendBufferSize)) == -1) {
             perror( "setsockopt( SO_SNDBUF )" );
             close(sockfd);
             return -1;
@@ -154,8 +149,7 @@ commonCode(int &sockfd, bool nodelay, int sendBufferSize, int recvBufferSize)
 
     // set the socket recv buffer size explicitly, or use the system default
     if ( recvBufferSize >= 0 ) {
-        if ( setsockopt( sockfd, SOL_SOCKET, SO_RCVBUF, (char*) &recvBufferSize,
-                         sizeof(recvBufferSize) ) == -1 ) {
+        if (setsockopt(sockfd, SOL_SOCKET, SO_RCVBUF, reinterpret_cast<char *>(&recvBufferSize), sizeof(recvBufferSize)) == -1) {
             perror( "setsockopt( SO_RCVBUF )" );
             close(sockfd);
             return -1;
@@ -223,8 +217,7 @@ serverSocket( struct in_addr host, unsigned short port,
 
     if ( reuse ) {
         int opt = 1;
-        if ( setsockopt( sockfd, SOL_SOCKET, SO_REUSEADDR,
-                         (char*) &opt, sizeof(int) ) == -1) {
+        if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, reinterpret_cast<char *>(&opt), sizeof(opt)) == -1) {
             perror( "setsockopt( SO_REUSEADDR )" );
             close( sockfd );
             return -1;