有时可以知道错误的数值，但是如果不知道对应于那个宏定义，也很难知道这个错误描述的是什么。我平时这两种方法来确定：在内核源码中搜索和查看头文件。 在内核源码中搜索一般都可以搜到，而且使用source insight的话也很方便，不多说了。当然更多的时候还是看头文件，因为一般的错误在/usr/include/asm-generic/errno-base.h和/usr/include/asm-generic/errno.h这个两个头文件中都可以找到，在/usr/include/bits/errno.h头文件中也有，但是很少。我写这篇的目的就是给哪些比较懒的同学，当然也给自己，下面我会贴出头文件中定义，这样便于查阅：

#defineEPERM 1/* Operation not permitted */

#defineENOENT 2/* No such file or directory */

#defineESRCH 3/* No such process */

#defineEINTR 4/* Interrupted system call */

#defineEIO 5/* I/O error */

#defineENXIO 6/* No such device or address */

#defineE2BIG 7/* Argument list too long */

#defineENOEXEC 8/* Exec format error */

#defineEBADF 9/* Bad file number */

#defineECHILD10/* No child processes */

#defineEAGAIN11/* Try again */

#defineENOMEM12/* Out of memory */

#defineEACCES13/* Permission denied */

#defineEFAULT14/* Bad address */

#defineENOTBLK15/* Block device required */

#defineEBUSY16/* Device or resource busy */

#defineEEXIST17/* File exists */

#defineEXDEV18/* Cross-device link */

#defineENODEV19/* No such device */

#defineENOTDIR20/* Not a directory */

#defineEISDIR21/* Is a directory */

#defineEINVAL22/* Invalid argument */

#defineENFILE23/* File table overflow */

#defineEMFILE24/* Too many open files */

#defineENOTTY25/* Not a typewriter */

#defineETXTBSY26/* Text file busy */

#defineEFBIG27/* File too large */

#defineENOSPC28/* No space left on device */

#defineESPIPE29/* Illegal seek */

#defineEROFS30/* Read-only file system */

#defineEMLINK31/* Too many links */

#defineEPIPE32/* Broken pipe */

#defineEDOM33/* Math argument out of domain of func */

#defineERANGE34/* Math result not representable */

#defineEDEADLK35/* Resource deadlock would occur */

#defineENAMETOOLONG36/* File name too long */

#defineENOLCK37/* No record locks available */

#defineENOSYS38/* Function not implemented */

#defineENOTEMPTY39/* Directory not empty */

#defineELOOP40/* Too many symbolic links encountered */

#defineEWOULDBLOCKEAGAIN/* Operation would block */

#defineENOMSG42/* No message of desired type */

#defineEIDRM43/* Identifier removed */

#defineECHRNG44/* Channel number out of range */

#defineEL2NSYNC45/* Level 2 not synchronized */

#defineEL3HLT46/* Level 3 halted */

#defineEL3RST47/* Level 3 reset */

#defineELNRNG48/* Link number out of range */

#defineEUNATCH49/* Protocol driver not attached */

#defineENOCSI50/* No CSI structure available */

#defineEL2HLT51/* Level 2 halted */

#defineEBADE52/* Invalid exchange */

#defineEBADR53/* Invalid request descriptor */

#defineEXFULL54/* Exchange full */

#defineENOANO55/* No anode */

#defineEBADRQC56/* Invalid request code */

#defineEBADSLT57/* Invalid slot */

#defineEDEADLOCKEDEADLK

#defineEBFONT59/* Bad font file format */

#defineENOSTR60/* Device not a stream */

#defineENODATA61/* No data available */

#defineETIME62/* Timer expired */

#defineENOSR63/* Out of streams resources */

#defineENONET64/* Machine is not on the network */

#defineENOPKG65/* Package not installed */

#defineEREMOTE66/* Object is remote */

#defineENOLINK67/* Link has been severed */

#defineEADV68/* Advertise error */

#defineESRMNT69/* Srmount error */

#defineECOMM70/* Communication error on send */

#defineEPROTO71/* Protocol error */

#defineEMULTIHOP72/* Multihop attempted */

#defineEDOTDOT73/* RFS specific error */

#defineEBADMSG74/* Not a data message */

#defineEOVERFLOW75/* Value too large for defined data type */

#defineENOTUNIQ76/* Name not unique on network */

#defineEBADFD77/* File descriptor in bad state */

#defineEREMCHG78/* Remote address changed */

#defineELIBACC79/* Can not access a needed shared library */

#defineELIBBAD80/* Accessing a corrupted shared library */

#defineELIBSCN81/* .lib section in a.out corrupted */

#defineELIBMAX82/* Attempting to link in too many shared libraries */

#defineELIBEXEC83/* Cannot exec a shared library directly */

#defineEILSEQ84/* Illegal byte sequence */

#defineERESTART85/* Interrupted system call should be restarted */

#defineESTRPIPE86/* Streams pipe error */

#defineEUSERS87/* Too many users */

#defineENOTSOCK88/* Socket operation on non-socket */

#defineEDESTADDRREQ89/* Destination address required */

#defineEMSGSIZE90/* Message too long */

#defineEPROTOTYPE91/* Protocol wrong type for socket */

#defineENOPROTOOPT92/* Protocol not available */

#defineEPROTONOSUPPORT93/* Protocol not supported */

#defineESOCKTNOSUPPORT94/* Socket type not supported */

#defineEOPNOTSUPP95/* Operation not supported on transport endpoint */

#defineEPFNOSUPPORT96/* Protocol family not supported */

#defineEAFNOSUPPORT97/* Address family not supported by protocol */

#defineEADDRINUSE98/* Address already in use */

#defineEADDRNOTAVAIL99/* Cannot assign requested address */

#defineENETDOWN100/* Network is down */

#defineENETUNREACH101/* Network is unreachable */

#defineENETRESET102/* Network dropped connection because of reset */

#defineECONNABORTED103/* Software caused connection abort */

#defineECONNRESET104/* Connection reset by peer */

#defineENOBUFS105/* No buffer space available */

#defineEISCONN106/* Transport endpoint is already connected */

#defineENOTCONN107/* Transport endpoint is not connected */

#defineESHUTDOWN108/* Cannot send after transport endpoint shutdown */

#defineETOOMANYREFS109/* Too many references: cannot splice */

#defineETIMEDOUT110/* Connection timed out */

#defineECONNREFUSED111/* Connection refused */

#defineEHOSTDOWN112/* Host is down */

#defineEHOSTUNREACH113/* No route to host */

#defineEALREADY114/* Operation already in progress */

#defineEINPROGRESS115/* Operation now in progress */

#defineESTALE116/* Stale NFS file handle */

#defineEUCLEAN117/* Structure needs cleaning */

#defineENOTNAM118/* Not a XENIX named type file */

#defineENAVAIL119/* No XENIX semaphores available */

#defineEISNAM120/* Is a named type file */

#defineEREMOTEIO121/* Remote I/O error */

#defineEDQUOT122/* Quota exceeded */

#defineENOMEDIUM123/* No medium found */

#defineEMEDIUMTYPE124/* Wrong medium type */

#defineECANCELED125/* Operation Canceled */

#defineENOKEY126/* Required key not available */

#defineEKEYEXPIRED127/* Key has expired */

#defineEKEYREVOKED128/* Key has been revoked */

#defineEKEYREJECTED129/* Key was rejected by service */

/* for robust mutexes */

#defineEOWNERDEAD130/* Owner died */

#defineENOTRECOVERABLE131/* State not recoverable */

#define ERFKILL132/* Operation not possible due to RF-kill */

#define EHWPOISON133/* Memory page has hardware error */