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Compiler Q's

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grv575:
Whether printf() is a builtin or not, it still requires the prototype: #include <stdio.h> is needed or I get an error on mingw.

vserghi:
I've been to the GNU GCC web site and had a look at the compiler options.

It is not immediatley obvious, which switches are being set when I place a check marks against some of the compiler options in C::B? I seem to remember another thread discussing something about giving users a description of what the options do, or maybe even what switch is being used for that compiler option.

Will this be a feature at somepoint?

Vasilis.

thomas:

--- Quote from: grv575 on August 08, 2005, 07:28:27 am ---Whether printf() is a builtin or not, it still requires the prototype: #include <stdio.h> is needed or I get an error on mingw.

--- End quote ---

Really? :)


--- Code: ---D:\desktop>echo main(){printf("blah");} > test.c

D:\desktop>gcc test.c -o test.exe

D:\desktop>test.exe
blah
D:\desktop>

--- End code ---

Urxae:
You're both right, sort of:

--- Code: ---D:\Temp> echo main(){printf("blah");} > test.c

D:\Temp> gcc -o test.exe test.c

D:\Temp> test
blah
D:\Temp> echo main(){printf("blah");} > test.cpp

D:\Temp> g++ -o test2.exe test.cpp
test.cpp: In function `int main()':
test.cpp:1: error: `printf' undeclared (first use this function)
test.cpp:1: error: (Each undeclared identifier is reported only once for each function it appears in.)

D:\Temp>
--- End code ---
So it'll work in C, but not in C++. C++ always requires prototypes/definitions, C just assumes that the parameter types are the types of what was passed and that it returns int if no prototype/definition is given (though GCC will warn about it if -Wall is passed).
However, since this thread was about C (Pelles C doesn't support C++) thomas is more right.
This is one of the things I dislike most about C.

-Wall, never compile C without it ;).

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