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std::map::insert returns a pair. Nothing you can do about that.
Your code should look like:
map<uint32_t, extsymbol> ::iterator extsymiter;
auto ret = procpointer->extsymcollector->insert({exsympointer->SYMESDID, * exsympointer });
if (ret.second)
extsymiter = ret.first;
else
If you don't care if the element was there or not, you can just skip the if.
Mircea
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thanks, I tried that
BTW I looked at the value of the iterator in storage and seems it prefixes my data with a int with the value of the entry number
Thank you again
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Hi Mainframe data big endian which I am trying to typedef 4 bytes I would rather not do it as int
I tried the following typedef char ESDID[4] where ESDID would represent 4 bytes
I also have this type ESDID in structure and would like to use it as a key
for example
struct syminfo
{
unsigned char recordtype;
unsigned char recordtypeflag;
ESDID symesdid;
BYTE seclen[4];
ESDID eseclen;
char* symname;
};
I am getting all sort of comple errors when I map it
syminfo* exsympointer = (syminfo*)procpointer->buffer;
procpointer->extsymcollector.insert(std::pair<ESDID, syminfo>(exsympointer->symesdid, *exsympointer));
The map is define as such
map<ESDID, syminfo> extsymcollector;
I think thesee aerror are from the way I tried to typdef ESDID if also tried to set as an struct type
struct ESDID
{
char x[4];
};
either way I get errors
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But you need the values of ESDID characters as key for the map.
something like this could do the trick
struct ESDID
{
char c[4];
uint32_t operator()(){return ((c[0] << 24) | (c[1] << 16) | (c[2] << 8) | c[3]); };
};
map <uint32_t, syminfo> m;
syminfo s1;
m.insert( pair<uint32_t, syminfo>(s1.symesdid(), s1) );
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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A few questions first of I am not on your level of C++ but i am getting there
so my first question is anytime you code a key as a structure you need code to tell it how to handle, format, compare that key ? is that right ?
second my data is big edian so DC F'10' lays out in storage 00000000 00000000 00000000 0000000A so the code shifts thngs back to little edian
as int x = 10 would be A0000000 00000000 00000000 00000000
your map statement below the structure why can it not be map <esdid, syminfo=""> m;
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Quote: so my first question is anytime you code a key as a structure you need code to tell it how to handle, format, compare that key ? is that right ?
Generally speaking, you haven't. However, in your scenario, you have to, because the key you need is the value stored inside the characters, not the reference to the struct.
Quote: second my data is big edian so DC F'10' lays out in storage 00000000 00000000 00000000 0000000A so the code shifts thngs back to little edian
as int x = 10 would be A0000000 00000000 00000000 00000000
Kind of that. Note you actually don't even need the key being big-endian.
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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Ok thank you again I am at work now I will compile it afterwards I have another map with a key made up of few elements in a structure
Had compile errors but I think if I do what you just did insert code in the the structure with a for lack of a better term dummy in-line call in the structure with the operator()() {}; I may be able to straighten it out a lot of this code I can use on the z/os mainframe so I am hoping outside of a few #ifdef _MSVC_ for the big Edian to little Edian conversion it will compile with the XL C\C++ compiler it too has a STL library thank you again
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Hi
I inserted the definitions you provided however I am still getting compile errors
struct ESDID
{
char c[4];
uint32_t operator()() { return ((c[0] << 24) | (c[1] << 16) | (c[2] << 8) | c[3]); };
};
C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.29.30133\include\xstddef(127,22): error C2676: binary '<': 'const _Ty' does not define this operator or a conversion to a type acceptable to the predefined operator
1> with
1> [
1> _Ty=ESDID
1> ]
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.29.30133\include\xstddef(126): message : while compiling class template member function 'bool std::less<ESDID>::operator ()(const _Ty &,const _Ty &) const'
1> with
1> [
1> _Ty=ESDID
1> ]
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.29.30133\include\xutility(1518): message : see reference to function template instantiation 'bool std::less<ESDID>::operator ()(const _Ty &,const _Ty &) const' being compiled
1> with
1> [
1> _Ty=ESDID
1> ]
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.29.30133\include\xmemory(1380): message : see reference to class template instantiation 'std::less<ESDID>' being compiled
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.29.30133\include\xmemory(1380): message : see reference to variable template 'const bool is_empty_v<std::less<ESDID> >' being compiled
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.29.30133\include\map(75): message : see reference to class template instantiation 'std::_Tree<std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,false>>' being compiled
1> with
1> [
1> _Kty=ESDID,
1> _Ty=extsymbol,
1> _Pr=std::less<ESDID>,
1> _Alloc=std::allocator<std::pair<const ESDID,extsymbol>>
1> ]
here is my definition of type extsymbol not quite sure where the error is from
struct extsymbol
{
unsigned char recordtype;
unsigned char recordtypeflag;
BYTE reserved1[4];
ESDID SYMESDID;
BYTE reserved2[4];
BYTE align[4];
BYTE seclen[4];
ESDID sumower;
BYTE reserved3[8];
BYTE nmeoffset[4];
BYTE nmelen[4];
BYTE aliasoffset[4];
BYTE alisnmelen;
char symname[63];
};
Here is the code the references extsymbol
case 0x0020:
{
extsymbol* exsympointer = (extsymbol*)procpointer->buffer;
procpointer->extsymcollector.insert({ exsympointer->SYMESDID, *exsympointer });
procpointer->extsymcollector.insert({ exsympointer->SYMESDID, *exsympointer });
}
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This
Quote: procpointer->extsymcollector.insert({ exsympointer->SYMESDID, *exsympointer });
should be instead
procpointer->extsymcollector.insert({ exsympointer->SYMESDID(), *exsympointer });
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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That gives a error of type mismatch me thinks I need a == operator inside struct esdid to tell it how to do the insert
I THINK ( because ) you are the expert anytime you try to insert a type struct the insert method needs to know how to compare therefore I think compare operators I.E == , < , >
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That (probably) gives type mismatch because you declared the map this way
map<ESDID, syminfo>
But you shouldn't do that. Instead you should declare it like
map <uint32_t, syminfo>
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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now I am I am getting
this
]
1>C:\SYSADATA\SYSADATA\SYSADATA\getnextsource.cpp(213,36): message : Element '1': no conversion from 'ESDID' to 'std::pair<const uint32_t,syminfo>'
1>C:\SYSADATA\SYSADATA\SYSADATA\getnextsource.cpp(213,36): message : Element '2': no conversion from 'syminfo' to 'std::pair<const uint32_t,syminfo>'
1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\VC\Tools\MSVC\14.29.30133\include\xtree(1283,10): message : see declaration of 'std::_Tree<std::_Tmap_traits<_Kty,_Ty,_Pr,_Alloc,false>>::insert'
1> with
1> [
1> _Kty=uint32_t,
1> _Ty=syminfo,
1> _Pr=std::less<uint32_t>,
1> _Alloc=std::allocator<std::pair<const uint32_t,syminfo>>
1> ]
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Did you try
procpointer->extsymcollector.insert(std::pair<uint32_t, syminfo>(exsympointer->SYMESDID(), *exsympointer )); ?
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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still getting type mismatch will have to look at this after work think it maybe using compare operators in the struct thank you
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The complier was screaming for < operator so I give it what wants hope this works got a clean complie
const struct ESDID
{
char c[4];
uint32_t operator()() { return ((c[0] << 24) | (c[1] << 16) | (c[2] << 8) | c[3]); };
BOOL operator< (const ESDID x) const { return c < x.c; }
};
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That compiles. However it is probably NOT what you want (both the key of the map and the < operator use the address of the c array).
Run
ESDID e1, e2;
e1.c[0] = e1.c[1] = e1.c[2] = e1.c[3] = 'A';
e2.c[0] = e2.c[1] = e2.c[2] = e2.c[3] = 'A';
cout << std::boolalpha;
cout << "(e1 < e2) " << (e1 < e2) << "\n";
cout << "(e2 < e1) " << (e2 < e1) << "\n";
and watch the resulting output. Can you spot the problem?
You can do something like this:
struct ESDID
{
char c[4];
operator uint32_t () const { return ((c[0] << 24) | (c[1] << 16) | (c[2] << 8) | c[3]); };
};
syminfo s1;
map <uint32_t, syminfo> m;
m.insert( pair<uint32_t, syminfo>(s1.symesdid, s1) );
Note the key of the map uses the content of the c array.
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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I understand the compare wont work correctly however what I dont see where the cast operator () is being used> Is dynamic cast used with pair i.e <> the same as the () operator ()
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The cast is used here:
pair<uint32_t, syminfo>(s1.symesdid, s1)
The compiler: "Map's key must be a uint32_t, hence s1.symesdid, being an ESDID, does NOT fit.
Let's see if there is a suitable cast..."
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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Alternatively you could use a union?
const struct ESDID
{
union
{
char c[4];
uint32_t i;
} x;
bool operator< (const ESDID e) const { return x.i < e.x.i; }
};
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thanks richard I dont see in the map documentation when using the insert method with key of type struct '<' operator must be overloaded by the user
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Actually there is (see std::map - cppreference.com[^]):
template<
class Key,
class T,
class Compare = std::less<Key>,
class Allocator = std::allocator<std::pair<const Key, T>>
> class map;As it should be, because the std::map is a sorted container.
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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cppreference.com:
template<
class Key,
class T,
class Compare = std::less<Key>,
class Allocator = std::allocator<std::pair<const Key, T>>
> class map;
Microsoft:
template <class Key,
class Type,
class Traits = less<Key>,
class Allocator=allocator<pair <const Key, Type>>>
class map;
Do you see significant differences?
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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I see the third parameter to the template in microsoft docs is class traits in the cpp reference its class compare thank you
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That's, you know, just a matter of naming...
BTW, you are welcome.
"In testa che avete, Signor di Ceprano?"
-- Rigoletto
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