strerror和erron参数函数的试用(经典)

strerror和erron参数函数的试用(经典)
2011年12月06日
　　linux下错误的捕获：errno和strerror的使用
　　经常在调用linux 系统api 的时候会出现一些错误，比方说使用open() write() creat()之类的函数有些时候会返回-1，也就是调用失败，这个时候往往需要知道失败的原因。这个时候使用errno这个全局变量就相当有用了。    在程序代码中包含 #include ,然后每次程序调用失败的时候，系统会自动用用错误代码填充errno这个全局变量，这样你只需要读errno这个全局变量就可以获得失败原因了。    例如：#include #include #include int main(void){int   fd;extern int errno;if((fd = open("/dev/dsp",O_WRONLY)) Socket operation on non-socket */#define EDESTADDRREQ 89 /* Destination address required */#define EMSGSIZE 90 /* Message too long */#define EPROTOTYPE 91 /* Protocol wrong type for socket */#define ENOPROTOOPT 92 /* Protocol not available */#define EPROTONOSUPPORT 93 /* Protocol not supported */#define ESOCKTNOSUPPORT 94 /* Socket type not supported */#define EOPNOTSUPP 95 /* Operation not supported on transport endpoint */#define EPFNOSUPPORT 96 /* Protocol family not supported */#define EAFNOSUPPORT 97 /* Address family not supported by protocol */#define EADDRINUSE 98 /* Address already in use */#define EADDRNOTAVAIL 99 /* Cannot assign requested address */#define ENETDOWN 100 /* Network is down */#define ENETUNREACH 101 /* Network is unreachable */#define ENETRESET 102 /* Network dropped connection because of reset */#define ECONNABORTED 103 /* Software caused connection abort */#define ECONNRESET 104 /* Connection reset by peer */#define ENOBUFS 105 /* No buffer space available */#define EISCONN 106 /* Transport endpoint is already connected */#define ENOTCONN 107 /* Transport endpoint is not connected */#define ESHUTDOWN 108 /* Cannot send after transport endpoint shutdown */#define ETOOMANYREFS 109 /* Too many references: cannot splice */#define ETIMEDOUT 110 /* Connection timed out */#define ECONNREFUSED 111 /* Connection refused */#define EHOSTDOWN 112 /* Host is down */#define EHOSTUNREACH 113 /* No route to host */#define EALREADY 114 /* Operation already in progress */#define EINPROGRESS 115 /* Operation now in progress */#define ESTALE 116 /* Stale NFS file handle */#define EUCLEAN 117 /* Structure needs cleaning */#define ENOTNAM 118 /* Not a XENIX named type file */#define ENAVAIL 119 /* No XENIX semaphores available */#define EISNAM 120 /* Is a named type file */#define EREMOTEIO 121 /* Remote I/O error */#define EDQUOT 122 /* Quota exceeded */#define ENOMEDIUM 123 /* No medium found */#define EMEDIUMTYPE 124 /* Wrong medium type */#endif同时也可以使用strerror（）来自己翻译如：#include #include #include int main(void){int   fd;extern int errno;if((fd = open("/dev/dsp",O_WRONLY)) < 0){   printf("errno=%d\n",errno);   char * mesg = strerror(errno);   printf("Mesg:%s\n",mesg);}  exit(0);}dsp设备忙的话将输出如下：errno=16Mesg:Device or resource busy