用Cygwin在vi编辑器中编写第一个C程序

Question

I [extremely] new to c programming and cygwin so thanks for being patient. I am using a PDF of Michael Vine's C programming for beginners and trying to enter and compile the first example.

Here is what i wrote in vi:

 #include <stdio.h>

main ()
{
printf("\nHello World\n");
}

When I try to compile using gcc , I get two errors:

1) usr/lib/gcc/i686-pc-cygwin/3.4.4./... /bin/ld:new: file format not recognized; treating as linked script usr/lib/gcc/i686-pc-cygwin/3.4.4./... /bin/ld:new: file format not recognized; treating as linked script

2) [same path as above]/bin/ld:new:11: syntax error collect2: ld returned 1 exit status

I'm pretty sure the actual syntax I used in vi is correct (its straight out of an example) and the gcc command is also correct. Am I missing a package or is my path to cygwin screwed up? Anyone know what's going on with this?

Answer 1

GCC, for better or for worse, uses the filename you pass to it to figure out what operation to do - run the compiler, the assembler, or the linker, or some combination, for example. Since you named your source file new , GCC is assuming it's a compiled object and is trying to link it. Either rename it new.c or pass the -xc flag when compiling.

For future reference, a good way to debug funny business with the GCC compiler driver is to pass the -v flag. If you do so for your original command line you'll see that it just invokes the linker, skipping the compilation step. An example from my machine:

$ gcc -v new -o new.exe
Using built-in specs.
Target: i686-apple-darwin11
Configured with: /private/var/tmp/llvmgcc42/llvmgcc42-2336.11~182/src/configure --disable-checking --enable-werror --prefix=/Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2 --mandir=/share/man --enable-languages=c,objc,c++,obj-c++ --program-prefix=llvm- --program-transform-name=/^[cg][^.-]*$/s/$/-4.2/ --with-slibdir=/usr/lib --build=i686-apple-darwin11 --enable-llvm=/private/var/tmp/llvmgcc42/llvmgcc42-2336.11~182/dst-llvmCore/Developer/usr/local --program-prefix=i686-apple-darwin11- --host=x86_64-apple-darwin11 --target=i686-apple-darwin11 --with-gxx-include-dir=/usr/include/c++/4.2.1
Thread model: posix
gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00)
 /usr/llvm-gcc-4.2/bin/../libexec/gcc/i686-apple-darwin11/4.2.1/collect2 -dynamic -arch x86_64 -macosx_version_min 10.8.4 -weak_reference_mismatches non-weak -o new.exe -lcrt1.10.6.o -L/usr/llvm-gcc-4.2/bin/../lib/gcc/i686-apple-darwin11/4.2.1/x86_64 -L/Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2/lib/gcc/i686-apple-darwin11/4.2.1/x86_64 -L/usr/llvm-gcc-4.2/bin/../lib/gcc/i686-apple-darwin11/4.2.1 -L/usr/llvm-gcc-4.2/bin/../lib/gcc -L/Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2/lib/gcc/i686-apple-darwin11/4.2.1 -L/usr/llvm-gcc-4.2/bin/../lib/gcc/i686-apple-darwin11/4.2.1/../../.. -L/Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2/lib/gcc/i686-apple-darwin11/4.2.1/../../.. new -lSystem -lgcc -lSystem
ld: warning: ignoring file new, file was built for unsupported file format ( 0x20 0x23 0x69 0x6e 0x63 0x6c 0x75 0x64 0x65 0x20 0x3c 0x73 0x74 0x64 0x69 0x6f ) which is not the architecture being linked (x86_64): new
Undefined symbols for architecture x86_64:
  "_main", referenced from:
      start in crt1.10.6.o
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status

Answer 2

One basic syntax error:

 ' main(){ ... } '

In C/C++, your main function should be:

'int main(){ ... }'