DEBUG_Printf 的一种定义（lwip）
#define LWIP_DBG_LEVEL_ALL 0x00
#define LWIP_DBG_LEVEL_OFF LWIP_DBG_LEVEL_ALL /* compatibility define only */
#define LWIP_DBG_LEVEL_WARNING 0x01 /* bad checksums, dropped packets, ... */
#define LWIP_DBG_LEVEL_SERIOUS 0x02 /* memory allocation failures, ... */
#define LWIP_DBG_LEVEL_SEVERE 0x03
#define LWIP_DBG_MASK_LEVEL 0x03
/** flag for LWIP_DEBUGF to enable that debug message */
#define LWIP_DBG_ON 0x80U
/** flag for LWIP_DEBUGF to disable that debug message */
#define LWIP_DBG_OFF 0x00U
/** flag for LWIP_DEBUGF indicating a tracing message (to follow program flow) */
#define LWIP_DBG_TRACE 0x40U
/** flag for LWIP_DEBUGF indicating a state debug message (to follow module states) */
#define LWIP_DBG_STATE 0x20U
/** flag for LWIP_DEBUGF indicating newly added code, not thoroughly tested yet */
#define LWIP_DBG_FRESH 0x10U
/** flag for LWIP_DEBUGF to halt after printing this debug message */
#define LWIP_DBG_HALT 0x08U
#ifndef SOCKETS_DEBUG
#define SOCKETS_DEBUG LWIP_DBG_OFF
#endif
/**
* ICMP_DEBUG: Enable debugging in icmp.c.
*/
#ifndef ICMP_DEBUG
#define ICMP_DEBUG LWIP_DBG_OFF
#endif
#ifdef LWIP_DEBUG
/** print debug message only if debug message type is enabled...
* AND is of correct type AND is at least LWIP_DBG_LEVEL
*/
#define LWIP_PLATFORM_DIAG printf
#define LWIP_DEBUGF(debug, message) do { \
if ( \
((debug) & LWIP_DBG_ON) && \
((debug) & LWIP_DBG_TYPES_ON) && \
((s16_t)((debug) & LWIP_DBG_MASK_LEVEL) >= LWIP_DBG_MIN_LEVEL)) { \
LWIP_PLATFORM_DIAG message; \
if ((debug) & LWIP_DBG_HALT) { \
while(1); \
} \
} \
} while(0)
#else /* LWIP_DEBUG */
#define LWIP_DEBUGF(debug, message)
#endif /* LWIP_DEBUG */
#endif /* __LWIP_DEBUG_H__ */
code:
case TCP_KEEPINTVL:
sock->conn->pcb.tcp->keep_intvl = 1000*(u32_t)(*(int*)optval);
LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_setsockopt(%d, IPPROTO_TCP, TCP_KEEPINTVL) -> %"U32_F"\n",
s, sock->conn->pcb.tcp->keep_intvl));