perl XS

概述h2xs -A FloatCalc 然后改写FloatCalc.xs，以下提供3种有别于标准写法的方式。 方式一： #define PERL_NO_GET_CONTEXT#include "EXTERN.h"#include "perl.h"#include "XSUB.h"#include <stdio.h>XS(XS_FloatCalc_pow){ dXS

h2xs -A floatCalc

然后改写floatCalc.xs，以下提供3种有别于标准写法的方式。

方式一：

#define PERL_NO_GET_CONTEXT#include "EXTERN.h"#include "perl.h"#include "XSUB.h"#include <stdio.h>XS(XS_floatCalc_pow){    dXSARGS;    if (items != 2)       croak("usage:floatCalc::pow(x,y)");    {		double	RETVAL;		dXSTARG;		RETVAL = pow(SvNV(ST(0)),SvNV(ST(1)) );		XSprePUSH; 		PUSHn(RETVAL);    }    XSRETURN(1);}XS(boot_floatCalc){    dXSARGS;    const char* file = __file__;	newXS("floatCalc::pow",XS_floatCalc_pow,file);	if (PL_unitcheckav)		call_List(PL_scopestack_ix,PL_unitcheckav);    XSRETURN_YES;}

方式二:

#define PERL_NO_GET_CONTEXT#include "EXTERN.h"#include "perl.h"#include "XSUB.h"#include <stdio.h>XS(XS_floatCalc_pow){    dXSARGS;    if (items != 2)       croak("usage:floatCalc::pow(x,y)");    {		double result;		sp = mark;		result = pow(SvNV(ST(0)),SvNV(ST(1)) );		xpuSHs(sv_2mortal(newSVnv(result)));    }    XSRETURN(1);}XS(boot_floatCalc){    dXSARGS;    const char* file = __file__;	newXS("floatCalc::pow",PL_unitcheckav);    XSRETURN_YES;}

方式三:

#define PERL_NO_GET_CONTEXT#include "EXTERN.h"#include "perl.h"#include "XSUB.h"#include <stdio.h>XS(XS_floatCalc_pow){    dSP; 			//得到sp    dAXMARK; 		//得到mark    dITEMS;			//得到items = sp - mark    if (items != 2)       croak("usage:floatCalc::pow(x,y)");    {		double result;		sp = mark;	//回到起始位置		result = pow(SvNV(ST(0)),SvNV(ST(1)) );		xpuSHs(sv_2mortal(newSVnv(result)));    }    PL_stack_sp = sp;	//返回栈帧	return;	}XS(boot_floatCalc){    dXSARGS;    const char* file = __file__;	newXS("floatCalc::pow",PL_unitcheckav);    XSRETURN_YES;}

方式四:

#define PERL_NO_GET_CONTEXT#include "EXTERN.h"#include "perl.h"#include "XSUB.h"#include <stdio.h>XS(XS_floatCalc_pow){    dXSARGS;    double result;    if (items != 2)    {       croak("usage:floatCalc::pow(x,y)");       XSRETURN_EMPTY;    }    result = pow(SvNV(ST(0)),SvNV(ST(1)) );    XSRETURN_NV(result);}XS(boot_floatCalc){    I32 ax = POPMARK;		//仅需要ax    const char* file = __file__;    newXS("floatCalc::pow",file);    if (PL_unitcheckav)        call_List(PL_scopestack_ix,PL_unitcheckav);    XSRETURN_YES;}

 方式五：

#define PERL_NO_GET_CONTEXT#include "EXTERN.h"#include "perl.h"#include "XSUB.h"#include <stdio.h>XS(XS_floatCalc_pow){    SV **mark = PL_stack_base + (*PL_markstack_ptr--);    int items = PL_stack_sp - mark;    double	result;    if (items != 2)    {       croak("usage:floatCalc::pow(x,y)");       PL_stack_sp = mark;       return;    }	result = pow(SvNV(mark[1+0]),SvNV(mark[1+1]) );	mark[1+0] = sv_2mortal(newSVnv(result));	PL_stack_sp = mark +1;	return;}XS(boot_floatCalc){    I32 ax = POPMARK;		//仅需要ax    const char* file = __file__;	newXS("floatCalc::pow",PL_unitcheckav);    XSRETURN_YES;}

 

测试:

#!/usr/bin/perluse floatCalc;my $result = pow(2.0,4.0);print "pow(2.0,4.0) = $result\n";my $result = pow(2.0);  # 会有用法提示<>;

结果:

C:\Users\G-SpIDer\floatCalc>test.plpow(2.0,4.0) = 16usage:floatCalc::pow(x,y) at C:\Users\G-SpIDer\Desktop\hello.pl line 6.

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