Question

早上好，我正在用C ++实现这个类，但它给OCTET_STRING类型带来了一些问题。事实上，删除那些变量，但显然我也需要它们。

class MIXIM_API BSMblob : public cObject
{
public:

        long     MsgCount;
        OCTET_STRING   TemporaryID;
        long     DSecond;
        long     Latitude;
        long     Longitude;
        OCTET_STRING   Elevation;
        OCTET_STRING   PositionalAccuracy;
        OCTET_STRING   TransmissionAndSpeed;
        long     Heading;
        OCTET_STRING   SteeringWheelAngle;
        OCTET_STRING   AccelerationSet4Way;
        OCTET_STRING   BrakeSystemStatus;

/*other line of codes */

    /** @brief Returns a string with the value of the BSMblobinate. */
    std::string info() const;

};


inline std::ostream& operator<<(std::ostream& os, const BSMblob& BSMblob)
{
   return os << "(" << BSMblob.MsgCount << "," << BSMblob.TemporaryID 
             << "," << BSMblob.DSecond << "," << BSMblob.Latitude 
             << "," << BSMblob.Longitude << "," << BSMblob.Elevation 
             << "," << BSMblob.PositionalAccuracy << "," << BSMblob.TransmissionAndSpeed 
             << "," << BSMblob.Heading << "," << BSMblob.SteeringWheelAngle 
             << "," << BSMblob.AccelerationSet4Way << "," << BSMblob.BrakeSystemStatus 
             << ")";
}

错误是=＆gt;错误：'operator＆lt;＆lt;'不匹配（操作数类型为'std :: basic_ostream'和'const OCTET_STRING'）

P.S。我也想知道是否可以将双变量转换为OCTET_STRING。

谢谢大家

这里是OCTET_STRING.h：

#ifndef _OCTET_STRING_H_
#define _OCTET_STRING_H_

#include <asn_application.h>

#ifdef __cplusplus
extern "C" {
#endif

typedef struct OCTET_STRING {
    uint8_t *buf;   /* Buffer with consecutive OCTET_STRING bits */
    int size;   /* Size of the buffer */

    asn_struct_ctx_t _asn_ctx;  /* Parsing across buffer boundaries */
} OCTET_STRING_t;

extern asn_TYPE_descriptor_t asn_DEF_OCTET_STRING;

asn_struct_free_f OCTET_STRING_free;
asn_struct_print_f OCTET_STRING_print;
asn_struct_print_f OCTET_STRING_print_utf8;
ber_type_decoder_f OCTET_STRING_decode_ber;
der_type_encoder_f OCTET_STRING_encode_der;
xer_type_decoder_f OCTET_STRING_decode_xer_hex;     /* Hexadecimal */
xer_type_decoder_f OCTET_STRING_decode_xer_binary;  /* 01010111010 */
xer_type_decoder_f OCTET_STRING_decode_xer_utf8;    /* ASCII/UTF-8 */
xer_type_encoder_f OCTET_STRING_encode_xer;
xer_type_encoder_f OCTET_STRING_encode_xer_utf8;
per_type_decoder_f OCTET_STRING_decode_uper;
per_type_encoder_f OCTET_STRING_encode_uper;

/******************************
 * Handy conversion routines. *
 ******************************/

/*
 * This function clears the previous value of the OCTET STRING (if any)
 * and then allocates a new memory with the specified content (str/size).
 * If size = -1, the size of the original string will be determined
 * using strlen(str).
 * If str equals to NULL, the function will silently clear the
 * current contents of the OCTET STRING.
 * Returns 0 if it was possible to perform operation, -1 otherwise.
 */
int OCTET_STRING_fromBuf(OCTET_STRING_t *s, const char *str, int size);

/* Handy conversion from the C string into the OCTET STRING. */
#define OCTET_STRING_fromString(s, str) OCTET_STRING_fromBuf(s, str, -1)

/*
 * Allocate and fill the new OCTET STRING and return a pointer to the newly
 * allocated object. NULL is permitted in str: the function will just allocate
 * empty OCTET STRING.
 */
OCTET_STRING_t *OCTET_STRING_new_fromBuf(asn_TYPE_descriptor_t *td,
    const char *str, int size);

/****************************
 * Internally useful stuff. *
 ****************************/

typedef struct asn_OCTET_STRING_specifics_s {
    /*
     * Target structure description.
     */
    int struct_size;    /* Size of the structure */
    int ctx_offset;     /* Offset of the asn_struct_ctx_t member */

    enum asn_OS_Subvariant {
        ASN_OSUBV_ANY,  /* The open type (ANY) */
        ASN_OSUBV_BIT,  /* BIT STRING */
        ASN_OSUBV_STR,  /* String types, not {BMP,Universal}String  */
        ASN_OSUBV_U16,  /* 16-bit character (BMPString) */
        ASN_OSUBV_U32   /* 32-bit character (UniversalString) */
    } subvariant;
} asn_OCTET_STRING_specifics_t;

#ifdef __cplusplus
}
#endif

#endif  /* _OCTET_STRING_H_ */

Answer 1

来自编译器的错误消息非常明确且明确：没有

std::ostream& operator<<(std::ostream&, OCTET_STRING const&);

它可以使用。如果OCTET_STRING是一个明智的C ++类型，那么所述运算符就已经实现了。它缺失的事实意味着永远不应该在I / O中使用OCTET_STRING，该类是由不太熟悉编程艺术的人提供的，或者它是一段C代码你在滥用。

要解决问题，要么放弃使用OCTET_STRING（最好），要么自己为所述运营商提供定义（理想情况为inline）。

请注意，OCTET_STRING 不是标准C ++类型。它appears是一些C结构和Windows的东西。使用它显然会导致问题，但也会使代码变得不可移植。我强烈建议避免使用 OCTET_STRING。我不知道OCTET_STRING做了什么，我不知道要用什么代替它，但也许你知道你用它做什么？即代码中Elevation的真实类型是什么？似乎double为大多数人做了工作，如果不是全部的话。

Answer 2

只写一个：

std::ostream& operator<<(std::ostream& os, const OCTET_STRING& whatever)
{
    // print to os
    return os;
}

错误：与C ++代码中的'operator＆lt;＆lt;'不匹配

2 个答案: