Duanxx C + + learning: gcc and g++

In fact, before this, I always thought that gcc and g++ is a thing, just have two different names only, today in Linux under the compilation of a C code error only to find the difference between GCC and g++.

First describe the error you encountered today:

Because before writing the program, write is CPP file, and then directly use g++ compile, no error, also did not care about these problems, today there is a C file, but contains after the STL vector syntax, think of using GCC to compile, the result error, error is: Can't find the vector.

What is gcc/g++

First, explain: gcc and gcc are two different things.

Gcc:gnu Compiler Collection (GUN compiler Collection), it can compile C, C + +, JAV, Fortran, Pascal, Object-c, Ada and other languages.

GCC is the gun C Compiler (C compiler) in GCC

G++ is the gun C + + Compiler (c + + compiler) in GCC

An interesting fact is that, in essence, gcc and g++ are not compilers, nor are they collections of compilers , they are just a drive, depending on the type of file to be compiled in the parameter, call the corresponding gun compiler, for example, to compile a C file with GCC, there are several steps:

Step1:call a preprocessor, like CPP.

Step2:call an actual compiler, like cc or cc1.

Step3:call an assembler, like as.

Step4:call a linker, like LD

because The compiler can be replaced , so GCC can not only compile C files

So, more accurately, GCC calls C compiler, and g++ calls C + + compiler

the main differences between GCC and g++

1. For *.c and *.cpp files, gcc is compiled as C and CPP files respectively (c and CPP are not the same syntax strength)

2. For *.c and *.cpp files, g++ is Unified as CPP file compilation

3. When compiling files using g++, g++ automatically links the standard library STL, and GCC does not automatically link the STL

4. GCC when compiling c file, can use the predetermined macros is relatively few

5. When compiling CPP files, gcc/g++ when compiling C files and CPP files (when both GCC and g++ invoke the CPP file compiler), some additional macros are added as follows:

#define __GXX_WEAK__ 1#define __cplusplus 1#define __deprecated 1#define __gnug__ 4#define __EXCEPTIONS 1#define __privat e_extern__ extern

6. When compiling C + + files with gcc, parameter –lstdc++ is required in order to be able to use STL, but this does not represent gcc–lstdc++ and g++ are equivalent , and they're not just the difference.

Main Parameters

-g-turn on debugging (so GDB gives morefriendly output)

-wall-turns on most warnings

-O Or-o2-turn on optimizations

-O <name>-Name of the output file

-c-output an Object file (. O)

-i<include path>-Specify an Includedirectory

-l<library path>-Specify a libdirectory

-l<library>-Link with librarylib<library>.a

Use example: g++-ohelloworld-i/homes/me/randomplace/include HelloWorld. C

Duanxx C + + learning: gcc and g++