<Div class = "motadou_spec_line"> 0 -- locate errno. H </div>
I want to see the content of errno. H. How do I know where it is? <Br/>
<Br/>
<Strong> Method 1: Search for errno. h. Command: Find/-name errno. H </strong>
<PRE class = "pre_style"> Find/-name errno. h
/Usr/include/ASM/errno. h
/Usr/include/ASM-generic/errno. h
/Usr/include/bits/errno. h
/Usr/include/errno. h
/Usr/include/Linux/errno. h
/Usr/include/sys/errno. h
</PRE>
Errno. h can be found. If you do not know the header file used by GCC, you need to make further judgments before confirmation.
<Br/>
<Br/>
<Strong> Method 2: view the search path of the header file during GCC compilation to determine the directory of errno. h. Command: gcc-V test. cpp </strong>
<PRE class = "pre_style"> GCC version 4.1.0 (SuSE Linux)
/Usr/lib/GCC/i586-suse-linux/4.1.0/cc1plus-quiet-v-d_gnu_source test. CPP-quiet-dumpbase test. CPP-mtune = generic-auxbase test-version-o/tmp/ccxnnd7y. s
# Include "..." search starts here:
# Include & lt;... & gt; search starts here:
/Usr/include/C ++/4.1.0
/Usr/include/C ++/4.1.0/i586-suse-linux
/Usr/include/C ++/4.1.0/backward
/Usr/local/include
/Usr/lib/GCC/i586-suse-linux/4.1.0/include
/Usr/lib/GCC/i586-suse-linux/4.1.0/http://www.cnblogs.com/http://www.cnblogs.com/i586-suse-linux/include
/Usr/include
End of search list.
</PRE>
The header file search path is listed above. Based on the file list obtained by the first method, the location of errno. h can be located.
<Br/>
<Br/>
The location of errno. h on my machine is: <br/>
/Usr/include/ASM-generic/errno-base.h <br/>
/Usr/include/ASM-generic/errno. H <br/>
<Div class = "motadou_spec_line"> 1 -- View errno instructions directly </div>
We can use "Man errno" to directly view the definition of errno, or use "man-a errno | col-B & gt; errno. man. <Br/>
<PRE class = "pre_style"> man-a errno | col-B & gt; errno. Man
Reformatting errno (3), please wait...
Reformatting errno (3 P), please wait...
Reformatting errno (3), please wait...
Reformatting errno. H (0 p), please wait...
</PRE>
<Div class = "motadou_spec_line"> 2 -- parsing the value and meaning of errno </div>
File:/usr/include/ASM-generic/errno-base.h
<PRE class = "pre_style"> # ifndef _ asm_generic_errno_base_h
# DEFINE _ asm_generic_errno_base_h
# 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 */
# Defineechild 10/* No Child processes */
# Defineeagain 11/* try again */
# Defineenomem 12/* out of memory */
# Defineeacces 13/* permission denied */
# Defineefault 14/* Bad address */
# Defineenotblk 15/* block device required */
# Defineebusy 16/* device or resource busy */
# Defineeexist 17/* file exists */
# Defineexdev 18/* cross-device link */
# Defineenodev 19/* no such device */
# Defineenotdir 20/* not a directory */
# Defineeisdir 21/* is a directory */
# Defineeinval 22/* invalid argument */
# Defineenfile 23/* file table overflow */
# Defineemfile 24/* too program open files */
# Defineenotty 25/* not a typewriter */
# Defineetxtbsy 26/* Text File busy */
# Defineefbig 27/* file too large */
# Defineenospc 28/* no space left on device */
# Defineespipe 29/* illegal seek */
# Defineerofs 30/* read-only file system */
# Defineemlink 31/* too many links */
# Defineepipe 32/* broken pipe */
# Defineedom 33/* Math argument out of domain of func */
# Defineerange 34/* Math result not representable */
# Endif
</PRE>
<Br/>
<Br/>
File:/usr/include/ASM-generic/errno. h
<PRE class = "pre_style"> # ifndef _ asm_generic_errno_h
# DEFINE _ asm_generic_errno_h
# Include & lt; ASM-generic/errno-base.h & gt;
# Defineedeadlk 35/* Resource deadlock wocould occur */
# Defineenametoolong36/* File Name Too Long */
# Defineenolck 37/* No record locks available */
# Defineenosys 38/* function not implemented */
# Defineenotempty39/* directory not empty */
# Defineeloop 40/* too define symbolic links encountered */
# Defineewouldblockeagain/* operation wo'd block */
# Defineenomsg 42/* No message of desired type */
# Defineeidrm 43/* identifier removed */
# Defineechrng 44/* channel number out of range */
# Defineel2nsync45/* level 2 not synchronized */
# Defineel3hlt 46/* level 3 halted */
# Defineel3rst 47/* level 3 reset */
# Defineelnrng 48/* Link number out of range */
# Defineeunatch 49/* protocol driver not attached */
# Defineenocsi 50/* No CSI structure available */
# Defineel2hlt 51/* level 2 halted */
# Defineebade 52/* invalid exchange */
# Defineebadr 53/* invalid request descriptor */
# Defineexfull 54/* exchange full */
# Defineenoano 55/* No anode */
# Defineebadrqc 56/* invalid request code */
# Defineebadslt 57/* invalid slot */
# Defineedeadlockedeadlk
# Defineebfont 59/* bad font file format */
# Defineenostr 60/* device not a stream */
# Defineenodata 61/* No data available */
# Defineetime 62/* timer expired */
# Defineenosr 63/* Out of streams Resources */
# Defineenonet 64/* machine is not on the Network */
# Defineenopkg 65/* package not installed */
# Defineeremote 66/* object is remote */
# Defineenolink 67/* link has been severed */
# Defineeadv 68/* advertise Error */
# Defineesrmnt 69/* srmount Error */
# Defineecomm 70/* communication error on send */
# Defineeproto 71/* Protocol Error */
# Defineemulti21372/* multihop attempted */
# Defineedotdot 73/* RFS specific error */
# Defineebadmsg 74/* not a data message */
# Defineeoverflow75/* value too large for defined data type */
# Defineenotuniq76/* name not unique on Network */
# Defineebadfd 77/* file descriptor in bad state */
# Defineeremchg 78/* remote address changed */
# Defineelibacc 79/* can not access a needed shared library */
# Defineelibbad 80/* accessing a specified upted shared library */
# Defineelibscn 81/*. Lib section in A. Out writable upted */
# Defineelibmax 82/* attempting to link in too functions shared libraries */
# Defineelibexec83/* cannot exec a shared library directly */
# Defineeilseq 84/* illegal byte sequence */
# Defineerestart85/* interrupted System Call shoshould be restarted */
# Defineestrpipe86/* streams pipe Error */
# Defineeusers 87/* too kerberusers */
# Defineenotsock88/* socket operation on Non-socket */
# Defineedestaddrreq89/* destination address required */
# Defineemsgsize90/* message too long */
# Defineeprototype91/* protocol wrong type for socket */
# Defineenoprotoopt92/* protocol not available */
# Defineeprotonosupp93 93/* protocol not supported */
# Defineesocktnosupp94 94/* socket type not supported */
# Defineeopnotsupp95/* operation not supported on transport endpoint */
# Defineepfnosupp96 96/* 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 */
# Defineenobufs 105/* No buffer space available */
# Defineeisconn 106/* transport endpoint is already connected */
# Defineenotconn107/* transport endpoint is not connected */
# Defineeshudown108/* cannot send after transport endpoint shutdown */
# Definepolicmanyrefs109/* too limit 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 */
# Defineestale 116/* stale NFS file handle */
# Defineeuclean 117/* structure needs cleaning */
# Defineenotnam 118/* Not a xenix named type file */
# Defineenavail 119/* No XENIX semaphores available */
# Defineeisnam 120/* is a named type file */
# Defineeremoteio121/* remote I/O Error */
# Defineedquot 122/* Quota exceeded */
# Defineenomedium123/* No medium found */
# Defineemediumtype124/* wrong medium type */
# Defineecanceled125/* operation canceled */
# Defineenokey 126/* 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 */
# Endif
</PRE>
