C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Visual C++ wrong entry point          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message Laurent Schall Guest Posted: Wed Mar 03, 2004 11:10 pm    Post subject: Visual C++ wrong entry point I experience a problem where starting an application compiled with visual C++ 6 SP5 does not execute the function main(int argc, char **argv) and exit immediately with code 1 (0x1). Putting main as an entry point in the section Project -> settings -> link -> output -> entry-point symbol, makes the program calling main but my argc and argv arguments are both equal to 0. Has anyone an idea ? Back to top John Harrison Guest Posted: Wed Mar 03, 2004 11:21 pm    Post subject: Re: Visual C++ wrong entry point "Laurent Schall" <schall_l (AT) yahoo (DOT) fr> wrote Quote: I experience a problem where starting an application compiled with visual C++ 6 SP5 does not execute the function main(int argc, char **argv) and exit immediately with code 1 (0x1). Putting main as an entry point in the section Project -> settings - link -> output -> entry-point symbol, makes the program calling main but my argc and argv arguments are both equal to 0. Has anyone an idea ? Maybe your program contains global objects whose constructors fail. Does this sound plausible? Setting the entry point under project settings sounds like a really bad idea, you were just messing with something you didn't understand. john Back to top Alf P. Steinbach Guest Posted: Wed Mar 03, 2004 11:31 pm    Post subject: Re: Visual C++ wrong entry point * [email]schall_l (AT) yahoo (DOT) fr[/email] (Laurent Schall) schriebt: Quote: I experience a problem where starting an application compiled with visual C++ 6 SP5 does not execute the function main(int argc, char **argv) and exit immediately with code 1 (0x1). As John Harrison responded, perhaps your program contains global objects whose constructors fail. Another possibility might be that you have used that compiler's non-standard feature where instead of 'main' a 'WinMain' or some such (there are actually several possibilities) is executed; in that case change the project settings or modify the compiler/linker arguments appropriately; see your documentation. Quote: Putting main as an entry point in the section Project -> settings - link -> output -> entry-point symbol, makes the program calling main but my argc and argv arguments are both equal to 0. Has anyone an idea? Yes, that is off-topic in this group, but in order to get you back on track: the entry point you specify to the linker, almost regardless of which C++ implementation, is _not_ the 'main' function, but some function in that C++ implementation's runtime library that in turn calls 'main'. Back to top Julie Guest Posted: Wed Mar 03, 2004 11:56 pm    Post subject: Re: Visual C++ wrong entry point Laurent Schall wrote: Quote: I experience a problem where starting an application compiled with visual C++ 6 SP5 does not execute the function main(int argc, char **argv) and exit immediately with code 1 (0x1). Putting main as an entry point in the section Project -> settings - link -> output -> entry-point symbol, makes the program calling main but my argc and argv arguments are both equal to 0. Has anyone an idea ? Main is defined as: int main(int argc, char * argv[]) I don't know if that will solve your problem or not, but it is a start. Back to top Johannes Bauer Guest Posted: Thu Mar 04, 2004 1:49 am    Post subject: Re: Visual C++ wrong entry point Julie wrote: Quote: Main is defined as: int main(int argc, char * argv[]) Which differs to Laurents definition (char** instead of char*[]) in what way? Johannes Back to top Julie Guest Posted: Thu Mar 04, 2004 2:10 am    Post subject: Re: Visual C++ wrong entry point Johannes Bauer wrote: Quote: Julie wrote: Main is defined as: int main(int argc, char * argv[]) Which differs to Laurents definition (char** instead of char*[]) in what way? Johannes Don't ask me -- ask the standards committee or refer to the current C++ standard. I was simply trying to point out that the OP's implementation of main wasn't conformant to the standard. My guess is that it might be possible that when the compiler/linker is resolving the call to main, it doesn't resolve to the OP's implementation, and thus resulted in their reported problem ??? Back to top Artie Gold Guest Posted: Thu Mar 04, 2004 4:29 am    Post subject: Re: Visual C++ wrong entry point Julie wrote: Quote: Johannes Bauer wrote: Julie wrote: Main is defined as: int main(int argc, char * argv[]) Which differs to Laurents definition (char** instead of char*[]) in what way? Johannes Don't ask me -- ask the standards committee or refer to the current C++ standard. I was simply trying to point out that the OP's implementation of main wasn't conformant to the standard. My guess is that it might be possible that when the compiler/linker is resolving the call to main, it doesn't resolve to the OP's implementation, and thus resulted in their reported problem ??? You miss the point. int main(int argc, char * argv[]) and int main(int argc, char ** argv) Are totally equivalent signatures. Indistinguishable to the compiler. HTH, --ag -- Artie Gold -- Austin, Texas "Yeah. It's an urban legend. But it's a *great* urban legend!" Back to top Julie Guest Posted: Thu Mar 04, 2004 4:50 am    Post subject: Re: Visual C++ wrong entry point Artie Gold wrote: Quote: You miss the point. int main(int argc, char * argv[]) and int main(int argc, char ** argv) Are totally equivalent signatures. Indistinguishable to the compiler. I didn't miss the point. Where in the standard does it say that *var[] is equivalent to **var or that they mangle the same, or that main can be implemented w/ char **? Back to top Alf P. Steinbach Guest Posted: Thu Mar 04, 2004 5:18 am    Post subject: Re: Visual C++ wrong entry point * Julie <julie (AT) aol (DOT) com> schriebt: Quote: Where in the standard does it say that *var[] is equivalent to **var or that they mangle the same, or that main can be implemented w/ char **? §8.3.5/3. This specifies what information is used to determine a function's type (otherwise known as its signature), which all declarations of a given function must agree on. First array parameters are changed to pointers. Then cv-qualifiers such as 'const' are deleted. Then e.g. 'register' is deleted. Then what you're left with is the function type. And that means, if I'm not totally mistaken, that int main( int const nArgs, char const * const * args ) is perfectly good -- actually a bit better, I'd suggest, than the example given in the standard... ;-) Back to top Mike Wahler Guest Posted: Thu Mar 04, 2004 10:00 am    Post subject: Re: Visual C++ wrong entry point "Julie" <julie (AT) aol (DOT) com> wrote Quote: Artie Gold wrote: You miss the point. int main(int argc, char * argv[]) and int main(int argc, char ** argv) Are totally equivalent signatures. Indistinguishable to the compiler. I didn't miss the point. I think you did. Quote: Where in the standard does it say that *var[] is equivalent to **var or that they mangle the same, No 'mangling' is occurring. Quote: or that main can be implemented w/ char **? ISO/IEC 14882:1998(E) [....] 8.3.5 Functions [....] 3 [...] The type of a function is determined using the following rules. The type of each parameter is determined from its own decl­ specifier­seq and declarator. After determining the type of each parameter, any parameter of type "array of T" or "function returning T" is adjusted to be "pointer to T" or "pointer to function returning T," respectively. -Mike Back to top Rob Williscroft Guest Posted: Thu Mar 04, 2004 12:15 pm    Post subject: Re: Visual C++ wrong entry point Alf P. Steinbach wrote in news:4046baf3.434241609 (AT) news (DOT) individual.net: Quote: * Julie <julie (AT) aol (DOT) com> schriebt: Where in the standard does it say that *var[] is equivalent to **var or that they mangle the same, or that main can be implemented w/ char **? §8.3.5/3. This specifies what information is used to determine a function's type (otherwise known as its signature), which all declarations of a given function must agree on. First array parameters are changed to pointers. Then cv-qualifiers such as 'const' are deleted. Then e.g. 'register' is deleted. Then what you're left with is the function type. And that means, if I'm not totally mistaken, that int main( int const nArgs, char const * const * args ) is perfectly good -- actually a bit better, I'd suggest, than the example given in the standard... ;-) Are you sure, I read the standard as saying the cv-qualifier modifying the paramiter type is removed, this is: char * const -> char *, not char const * -> char *. In essence char * const and char * are different cv-qualifications of the same type, where as char const * and char * are different types. So int main( int const, char ** const ); is as much "const" as you can legaly add to the usual int main( int, char ** ); Rob. -- http://www.victim-prime.dsl.pipex.com/ Back to top Alf P. Steinbach Guest Posted: Thu Mar 04, 2004 12:43 pm    Post subject: Re: Visual C++ wrong entry point * Rob Williscroft <rtw (AT) freenet (DOT) REMOVE.co.uk> schriebt: Quote: Alf P. Steinbach wrote in news:4046baf3.434241609 (AT) news (DOT) individual.net: * Julie <julie (AT) aol (DOT) com> schriebt: Where in the standard does it say that *var[] is equivalent to **var or that they mangle the same, or that main can be implemented w/ char **? §8.3.5/3. This specifies what information is used to determine a function's type (otherwise known as its signature), which all declarations of a given function must agree on. First array parameters are changed to pointers. Then cv-qualifiers such as 'const' are deleted. Then e.g. 'register' is deleted. Then what you're left with is the function type. And that means, if I'm not totally mistaken, that int main( int const nArgs, char const * const * args ) is perfectly good -- actually a bit better, I'd suggest, than the example given in the standard... ;-) Are you sure, I read the standard as saying the cv-qualifier modifying the paramiter type is removed, this is: char * const -> char *, not char const * -> char *. In essence char * const and char * are different cv-qualifications of the same type, where as char const * and char * are different types. So int main( int const, char ** const ); is as much "const" as you can legaly add to the usual int main( int, char ** ); Your interpretation seems much more reasonable and correct, yes. After all it's logical that a const at the outermost level doesn't affect what you can pass as actual arguments, whereas other const's will. But I _like_ that version of 'main', I _want_ that version of 'main'... ;-) -- A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing? A: Top-posting. Q: What is the most annoying thing on usenet and in e-mail? Back to top Default User Guest Posted: Thu Mar 04, 2004 7:36 pm    Post subject: Re: Visual C++ wrong entry point Julie wrote: Quote: Where in the standard does it say that *var[] is equivalent to **var or that they mangle the same, or that main can be implemented w/ char **? The C standard helpfully adds a footnote for those who don't know that * and [] are completely equivalent in function signatures: 8) Thus, int can be replaced by a typedef name defined as int, or the type of argv can be written as char ** argv, and so on. Brian Rodenborn Back to top Julie Guest Posted: Thu Mar 04, 2004 8:37 pm    Post subject: Re: Visual C++ wrong entry point Default User wrote: Quote: Julie wrote: Where in the standard does it say that *var[] is equivalent to **var or that they mangle the same, or that main can be implemented w/ char **? The C standard helpfully adds a footnote for those who don't know that * and [] are completely equivalent in function signatures: 8) Thus, int can be replaced by a typedef name defined as int, or the type of argv can be written as char ** argv, and so on. Brian Rodenborn I was not aware -- thanks to all that have pointed me in the right direction in the standard. I stand corrected, char ** argv to char * argv[] will most likely *not* solve the OP's problem. 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