Putenv yog dab tsi?
Putenv yog dab tsi?

Video: Putenv yog dab tsi?

Video: Putenv yog dab tsi?
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Kev piav qhia. Cov puv () kev ua haujlwm yuav tsum siv txoj hlua sib cav los teeb tsa ib puag ncig tus nqi sib txawv. Cov hlua sib cav yuav tsum taw tes rau ib txoj hlua ntawm daim ntawv "name = tus nqi". Cov puv () kev ua haujlwm yuav tsum ua kom tus nqi ntawm ib puag ncig hloov pauv lub npe sib npaug ntawm tus nqi los ntawm kev hloov pauv qhov hloov pauv uas twb muaj lawm lossis tsim ib qho tshiab

Xav txog qhov no, Getenv yog dab tsi?

Cov getenv ua () muaj nuj nqi tshawb xyuas cov npe ib puag ncig kom pom lub npe hloov pauv ib puag ncig, thiab xa rov qab tus taw tes rau tus nqi sib thooj. GNU-specific secure_getenv() muaj nuj nqi zoo ib yam li getenv ua () tshwj tsis yog tias nws rov NULL nyob rau hauv cov ntaub ntawv uas yuav tsum tau "kev ruaj ntseg execution".

Kuj Paub, PHP ib puag ncig hloov pauv yog dab tsi? Ib puag ncig hloov pauv txhais PHP ib puag ncig hloov pauv tso cai rau koj cov ntawv sau cia qee yam ntawm cov ntaub ntawv dynamically ntawm lub server. Qhov no txhawb cov ntawv hloov tau yooj yim hauv lub server uas muaj peev xwm hloov pauv ib puag ncig.

Cia li saib qhov no, Setenv yog dab tsi?

Kev piav qhia. setenv yog ib tug built-in muaj nuj nqi ntawm lub plhaub C (csh). Nws yog siv los txhais tus nqi ntawm ib puag ncig hloov pauv. Yog setenv yog muab tsis muaj kev sib cav, nws qhia tag nrho cov kev hloov pauv ib puag ncig thiab lawv cov txiaj ntsig. Yog tias ob qho tib si VAR thiab VALUE yog tau teev tseg, nws teev qhov sib txawv npe hu ua VAR rau tus nqi VALUE.

Strdup rov qab los li cas?

strdup ua (): Qhov no muaj nuj nqi rov qab los ib tug pointer rau ib tug null-terminated byte hlua, uas yog ib tug duplicate ntawm cov hlua taw tes rau los ntawm s. Lub cim xeeb tau ua tiav dynamically siv malloc thiab yog li nws tuaj yeem raug tso tawm siv dawb (). Nws rov qab los tus taw tes rau txoj hlua duplicated s. // thiab pointer rau luam yog rov qab los.

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