字符测试篇isalnumisalphaisasciiiscntrlisdigitisgraphisislowerisprintisspaceispunctisupperisxdigit字符串转换篇atofatoiatolgcvtstrtodstrtolstrtoultoasciitolowertoupper内存控制篇callocfreegetpagesizemallocmmapmunmap日期时间篇asctimectimegettimeofdaygmtimelocaltimemktimesettimeofdaytime内存及字符串操作篇bcmpbcopybzeroindexmemccpymemchrmemcmpmemcpymemmovememsetrindexstrcasecmpstrcatstrchrstrcmpstrcollstrcpystrcspnstrdupstrlenstrncasecmpstrncatstrncpystrpbrkstrrchrstrspnstrstrstrtok常用数学函数篇absacosasinatanatan2ceilcoscoshexpfrexpldexploglog10powsinsinhsqrttantanh用户组篇endgrentendpwentendutentfgetgrentfgetpwentgetegidgeteuidgetgidgetgrentgetgrgidgetgrnamgetgroupsgetpwgetpwentgetpwnamgetpwuidgetuidgetutentgetutidgetutlineinitgroupspututlineseteuidsetfsgidsetfsuidsetgidsetgrentsetgroupssetpwentsetregidsetreuidsetuidsetutentutmpname数据结构及算法篇cryptbsearchlfindlsearchqsortrandsrand文件操作篇closecreatdupdup2fcntlflockfsynclseekmkstempopenreadsyncwrite文件内容操作篇clearerrfclosefdopenfeoffflushfgetcfgetsfilenofopenfputcfputsfreadfreopenfseekftellfwritegetcgetchargetsmktempputcputcharrewindsetbufsetbuffersetlinebufsetvbufungetc进程操作篇atexitexeclexeclpexecvexecveexecvpexit_exitvforkgetpgidgetpgrpgetpidgetppidgetpriorityniceon_exitsetpgidsetpgrpsetprioritysystemwaitwaitpidfprintffscanfprintfsacnfsprintfsscanfvfprintfvfscanfvprintfvscanfvsprintfvsscanf文件权限控制篇accessalphasortchdirchmodchownchrootclosedirfchdirfchmodfchownfstatftruncategetcwdlinklstatopendirreaddirreadlinkremoverenamerewinddirseekdirstatsymlinktelldirtruncateumaskunlinkutimeutimes信号处理篇alarmkillpausesigactionsigaddsetsigdelsetsigemptysetsigfillsetsigismembersignalsigpendingsigprocmasksleepferrorperrorstrerrormkfifopclosepipepopen接口处理篇acceptbindconnectendprotoentendserventgetsockopthtonlhtonsinet_addrinet_atoninet_ntoalistenntohlntohsrecvrecvfromrecvmsgsendsendmsgsendtosetprotoentsetserventsetsockoptshutdownsocket环境变量篇getenvputenvsetenv终端控制篇getoptisattyselectttyname