Explicitly ignore return value or bare expression (macro expands to a number)

Paul Thompson · Paul Thompson · commit 449541c46426 · 2018-04-12T09:45:25.000-07:00
Compile: lwip_stack.c
In file included from ../features/FEATURE_LWIP/lwip-interface/lwip_stack.c:41:0:
../features/FEATURE_LWIP/lwip-interface/lwip_stack.c: In function 'mbed_lwip_bringup_2':
../features/FEATURE_LWIP/lwip-interface/ppp_lwip.h:58:44: warning: statement with no effect [-Wunused-value]
 #define ppp_lwip_disconnect()              ERR_IF
                                            ^
../features/FEATURE_LWIP/lwip-interface/lwip_stack.c:858:21: note: in expansion of macro 'ppp_lwip_disconnect'
                     ppp_lwip_disconnect();
                     ^~~~~~~~~~~~~~~~~~~
../features/FEATURE_LWIP/lwip-interface/ppp_lwip.h:58:44: warning: statement with no effect [-Wunused-value]
 #define ppp_lwip_disconnect()              ERR_IF
                                            ^
../features/FEATURE_LWIP/lwip-interface/lwip_stack.c:875:21: note: in expansion of macro 'ppp_lwip_disconnect'
                     ppp_lwip_disconnect();

                     ^~~~~~~~~~~~~~~~~~~
diff --git a/features/FEATURE_LWIP/lwip-interface/lwip_stack.c b/features/FEATURE_LWIP/lwip-interface/lwip_stack.c
@@ -855,7 +855,7 @@ nsapi_error_t mbed_lwip_bringup_2(bool dhcp, bool ppp, const char *ip, const cha
         if (lwip_blocking) {
             if (sys_arch_sem_wait(&lwip_netif_linked, 15000) == SYS_ARCH_TIMEOUT) {
                 if (ppp) {
-                    ppp_lwip_disconnect();
+                    (void)ppp_lwip_disconnect();
                 }
                 return NSAPI_ERROR_NO_CONNECTION;
             }
@@ -872,7 +872,7 @@ nsapi_error_t mbed_lwip_bringup_2(bool dhcp, bool ppp, const char *ip, const cha
         if (!mbed_lwip_get_ip_addr(true, &lwip_netif)) {
             if (sys_arch_sem_wait(&lwip_netif_has_any_addr, DHCP_TIMEOUT * 1000) == SYS_ARCH_TIMEOUT) {
                 if (ppp) {
-                    ppp_lwip_disconnect();
+                    (void)ppp_lwip_disconnect();
                 }
                 return NSAPI_ERROR_DHCP_FAILURE;
             }

Original file line number	Diff line number	Diff line change
`@@ -855,7 +855,7 @@ nsapi_error_t mbed_lwip_bringup_2(bool dhcp, bool ppp, const char *ip, const cha`
`855`	`855`	`if (lwip_blocking) {`
`856`	`856`	`if (sys_arch_sem_wait(&lwip_netif_linked, 15000) == SYS_ARCH_TIMEOUT) {`
`857`	`857`	`if (ppp) {`
`858`		`- ppp_lwip_disconnect();`
	`858`	`+ (void)ppp_lwip_disconnect();`
`859`	`859`	`}`
`860`	`860`	`return NSAPI_ERROR_NO_CONNECTION;`
`861`	`861`	`}`
`@@ -872,7 +872,7 @@ nsapi_error_t mbed_lwip_bringup_2(bool dhcp, bool ppp, const char *ip, const cha`
`872`	`872`	`if (!mbed_lwip_get_ip_addr(true, &lwip_netif)) {`
`873`	`873`	`if (sys_arch_sem_wait(&lwip_netif_has_any_addr, DHCP_TIMEOUT * 1000) == SYS_ARCH_TIMEOUT) {`
`874`	`874`	`if (ppp) {`
`875`		`- ppp_lwip_disconnect();`
	`875`	`+ (void)ppp_lwip_disconnect();`
`876`	`876`	`}`
`877`	`877`	`return NSAPI_ERROR_DHCP_FAILURE;`
`878`	`878`	`}`