Compiling gsoap for x64 with Visual Studio: C4302 conversion: truncation from void* to unsigned int
I am trying to compile gsoap with VS 2017 for x64. There's a compiler warning because void* (64bit address) is casted to unsigned int (32bit integer). It occurs at h = soap_hash_ptr(p) where p is the void* and h is the unsigned int.
That looks critical - I therefore had a look into stdsoap2.cpp of the current gsoap version - there however soap_hash_ptr seems to do the same through PtrToUlong - I want to keep gsoap which is great - but can I still rely on - possibly yes, because the return value of soap_hash_ptr is used as an index for an array or vector (either soap->mht or soap->pht) - however I am not yet quite shure - can someone give me a hint? Thank you.
- IDE: VS2017
- Target: x64
- gsoap version: Approx year 2005
64bit gsoap
asked Nov 13 '18 at 16:38
wepowepo
61
add a comment |
I am trying to compile gsoap with VS 2017 for x64. There's a compiler warning because void* (64bit address) is casted to unsigned int (32bit integer). It occurs at h = soap_hash_ptr(p) where p is the void* and h is the unsigned int.
That looks critical - I therefore had a look into stdsoap2.cpp of the current gsoap version - there however soap_hash_ptr seems to do the same through PtrToUlong - I want to keep gsoap which is great - but can I still rely on - possibly yes, because the return value of soap_hash_ptr is used as an index for an array or vector (either soap->mht or soap->pht) - however I am not yet quite shure - can someone give me a hint? Thank you.
- IDE: VS2017
- Target: x64
- gsoap version: Approx year 2005
64bit gsoap
asked Nov 13 '18 at 16:38
wepowepo
61
This seems fine to me, sincePtrToUlongis used to convert a pointer to an int which is then taken moduloSOAP_PTRHASH(with& (SOAP_PTRHASH-1)) to index a hash table. This can't possibly go wrong. It's just hashing into a table. I suggest to change the code in stdsoap2.h to#define soap_hash_ptr(p) ((size_t)((PtrToUlong(p) >> 3) & (SOAP_PTRHASH - 1)))
– Dr. Alex RE
Nov 15 '18 at 21:58
add a comment |
I am trying to compile gsoap with VS 2017 for x64. There's a compiler warning because void* (64bit address) is casted to unsigned int (32bit integer). It occurs at h = soap_hash_ptr(p) where p is the void* and h is the unsigned int.
That looks critical - I therefore had a look into stdsoap2.cpp of the current gsoap version - there however soap_hash_ptr seems to do the same through PtrToUlong - I want to keep gsoap which is great - but can I still rely on - possibly yes, because the return value of soap_hash_ptr is used as an index for an array or vector (either soap->mht or soap->pht) - however I am not yet quite shure - can someone give me a hint? Thank you.
- IDE: VS2017
- Target: x64
- gsoap version: Approx year 2005
64bit gsoap
asked Nov 13 '18 at 16:38
wepowepo
61
I am trying to compile gsoap with VS 2017 for x64. There's a compiler warning because void* (64bit address) is casted to unsigned int (32bit integer). It occurs at h = soap_hash_ptr(p) where p is the void* and h is the unsigned int.
That looks critical - I therefore had a look into stdsoap2.cpp of the current gsoap version - there however soap_hash_ptr seems to do the same through PtrToUlong - I want to keep gsoap which is great - but can I still rely on - possibly yes, because the return value of soap_hash_ptr is used as an index for an array or vector (either soap->mht or soap->pht) - however I am not yet quite shure - can someone give me a hint? Thank you.
- IDE: VS2017
- Target: x64
- gsoap version: Approx year 2005
64bit gsoap
64bit gsoap
asked Nov 13 '18 at 16:38
wepowepo
61
asked Nov 13 '18 at 16:38
wepowepo
61
edited Nov 14 '18 at 9:29
wepo
asked Nov 13 '18 at 16:38
wepowepo
61
asked Nov 13 '18 at 16:38
wepowepo
61
asked Nov 13 '18 at 16:38
wepowepo
61
61
This seems fine to me, sincePtrToUlongis used to convert a pointer to an int which is then taken moduloSOAP_PTRHASH(with& (SOAP_PTRHASH-1)) to index a hash table. This can't possibly go wrong. It's just hashing into a table. I suggest to change the code in stdsoap2.h to#define soap_hash_ptr(p) ((size_t)((PtrToUlong(p) >> 3) & (SOAP_PTRHASH - 1)))
– Dr. Alex RE
Nov 15 '18 at 21:58
add a comment |
This seems fine to me, sincePtrToUlongis used to convert a pointer to an int which is then taken moduloSOAP_PTRHASH(with& (SOAP_PTRHASH-1)) to index a hash table. This can't possibly go wrong. It's just hashing into a table. I suggest to change the code in stdsoap2.h to#define soap_hash_ptr(p) ((size_t)((PtrToUlong(p) >> 3) & (SOAP_PTRHASH - 1)))
– Dr. Alex RE
Nov 15 '18 at 21:58
This seems fine to me, since
PtrToUlong is used to convert a pointer to an int which is then taken modulo SOAP_PTRHASH (with & (SOAP_PTRHASH-1)) to index a hash table. This can't possibly go wrong. It's just hashing into a table. I suggest to change the code in stdsoap2.h to #define soap_hash_ptr(p) ((size_t)((PtrToUlong(p) >> 3) & (SOAP_PTRHASH - 1)))– Dr. Alex RE
Nov 15 '18 at 21:58
This seems fine to me, since
PtrToUlong is used to convert a pointer to an int which is then taken modulo SOAP_PTRHASH (with & (SOAP_PTRHASH-1)) to index a hash table. This can't possibly go wrong. It's just hashing into a table. I suggest to change the code in stdsoap2.h to #define soap_hash_ptr(p) ((size_t)((PtrToUlong(p) >> 3) & (SOAP_PTRHASH - 1)))– Dr. Alex RE
Nov 15 '18 at 21:58
add a comment |
1 Answer
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The PtrToUlong is correctly used to truncate the pointer, as this is actually recommended by the Win64 rules for using pointers https://docs.microsoft.com/en-us/windows/desktop/winprog64/rules-for-using-pointers
- Use the PtrToLong or PtrToUlong function to truncate pointers.
If you must truncate a pointer to a 32-bit value, use the PtrToLong or
PtrToUlong function (defined in Basetsd.h). These functions disable
the pointer truncation warning for the duration of the call.
The soap_hash_ptr macro that you quote is used to compute an index into a hash table:
#if defined(WIN32) && !defined(UNDER_CE)
#define soap_hash_ptr(p) ((PtrToUlong(p) >> 3) & (SOAP_PTRHASH - 1))
#else
#define soap_hash_ptr(p) ((size_t)(((unsigned long)(p) >> 3) & (SOAP_PTRHASH-1)))
#endif
This definition and its use to index a table cannot cause an issues.
answered Nov 18 '18 at 14:47
Dr. Alex REDr. Alex RE
733617
add a comment |
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1 Answer
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active
oldest
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
The PtrToUlong is correctly used to truncate the pointer, as this is actually recommended by the Win64 rules for using pointers https://docs.microsoft.com/en-us/windows/desktop/winprog64/rules-for-using-pointers
- Use the PtrToLong or PtrToUlong function to truncate pointers.
If you must truncate a pointer to a 32-bit value, use the PtrToLong or
PtrToUlong function (defined in Basetsd.h). These functions disable
the pointer truncation warning for the duration of the call.
The soap_hash_ptr macro that you quote is used to compute an index into a hash table:
#if defined(WIN32) && !defined(UNDER_CE)
#define soap_hash_ptr(p) ((PtrToUlong(p) >> 3) & (SOAP_PTRHASH - 1))
#else
#define soap_hash_ptr(p) ((size_t)(((unsigned long)(p) >> 3) & (SOAP_PTRHASH-1)))
#endif
This definition and its use to index a table cannot cause an issues.
answered Nov 18 '18 at 14:47
Dr. Alex REDr. Alex RE
733617
add a comment |
The PtrToUlong is correctly used to truncate the pointer, as this is actually recommended by the Win64 rules for using pointers https://docs.microsoft.com/en-us/windows/desktop/winprog64/rules-for-using-pointers
- Use the PtrToLong or PtrToUlong function to truncate pointers.
If you must truncate a pointer to a 32-bit value, use the PtrToLong or
PtrToUlong function (defined in Basetsd.h). These functions disable
the pointer truncation warning for the duration of the call.
The soap_hash_ptr macro that you quote is used to compute an index into a hash table:
#if defined(WIN32) && !defined(UNDER_CE)
#define soap_hash_ptr(p) ((PtrToUlong(p) >> 3) & (SOAP_PTRHASH - 1))
#else
#define soap_hash_ptr(p) ((size_t)(((unsigned long)(p) >> 3) & (SOAP_PTRHASH-1)))
#endif
This definition and its use to index a table cannot cause an issues.
answered Nov 18 '18 at 14:47
Dr. Alex REDr. Alex RE
733617
add a comment |
The PtrToUlong is correctly used to truncate the pointer, as this is actually recommended by the Win64 rules for using pointers https://docs.microsoft.com/en-us/windows/desktop/winprog64/rules-for-using-pointers
- Use the PtrToLong or PtrToUlong function to truncate pointers.
If you must truncate a pointer to a 32-bit value, use the PtrToLong or
PtrToUlong function (defined in Basetsd.h). These functions disable
the pointer truncation warning for the duration of the call.
The soap_hash_ptr macro that you quote is used to compute an index into a hash table:
#if defined(WIN32) && !defined(UNDER_CE)
#define soap_hash_ptr(p) ((PtrToUlong(p) >> 3) & (SOAP_PTRHASH - 1))
#else
#define soap_hash_ptr(p) ((size_t)(((unsigned long)(p) >> 3) & (SOAP_PTRHASH-1)))
#endif
This definition and its use to index a table cannot cause an issues.
answered Nov 18 '18 at 14:47
Dr. Alex REDr. Alex RE
733617
The PtrToUlong is correctly used to truncate the pointer, as this is actually recommended by the Win64 rules for using pointers https://docs.microsoft.com/en-us/windows/desktop/winprog64/rules-for-using-pointers
- Use the PtrToLong or PtrToUlong function to truncate pointers.
If you must truncate a pointer to a 32-bit value, use the PtrToLong or
PtrToUlong function (defined in Basetsd.h). These functions disable
the pointer truncation warning for the duration of the call.
The soap_hash_ptr macro that you quote is used to compute an index into a hash table:
#if defined(WIN32) && !defined(UNDER_CE)
#define soap_hash_ptr(p) ((PtrToUlong(p) >> 3) & (SOAP_PTRHASH - 1))
#else
#define soap_hash_ptr(p) ((size_t)(((unsigned long)(p) >> 3) & (SOAP_PTRHASH-1)))
#endif
This definition and its use to index a table cannot cause an issues.
answered Nov 18 '18 at 14:47
Dr. Alex REDr. Alex RE
733617
answered Nov 18 '18 at 14:47
Dr. Alex REDr. Alex RE
733617
answered Nov 18 '18 at 14:47
Dr. Alex REDr. Alex RE
733617
answered Nov 18 '18 at 14:47
Dr. Alex REDr. Alex RE
733617
733617
add a comment |
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This seems fine to me, since
PtrToUlongis used to convert a pointer to an int which is then taken moduloSOAP_PTRHASH(with& (SOAP_PTRHASH-1)) to index a hash table. This can't possibly go wrong. It's just hashing into a table. I suggest to change the code in stdsoap2.h to#define soap_hash_ptr(p) ((size_t)((PtrToUlong(p) >> 3) & (SOAP_PTRHASH - 1)))– Dr. Alex RE
Nov 15 '18 at 21:58