fcntl编译C++问题

Question

{net04:~/xxxx/wip} gcc -o  write_test write_test.c
In file included from write_test.c:4:
global.h:10: warning: `b' initialized and declared `extern'

这段代码使用fcntl.h和定义的文件处理函数，如open()、write()、close()等。代码可以按预期进行编译和工作。

{net04:~/xxxx/wip} gcc -o  write_test write_test.cpp
In file included from write_test.cpp:4:
global.h:10: warning: `b' initialized and declared `extern'
write_test.cpp: In function `int main()':
write_test.cpp:56: error: `exit' undeclared (first use this function)
write_test.cpp:56: error: (Each undeclared identifier is reported only once for each function it appears in.)
write_test.cpp:58: error: `write' undeclared (first use this function)
write_test.cpp:62: error: `close' undeclared (first use this function)

当我把它作为CPP源码使用时，为什么GCC会抱怨？奇怪的是，它为什么不抱怨open()呢？这到底是怎么回事？

Answer 1

1. C++对头文件有更严格的要求--你需要：#include <unistd.h>来正确获取indicated.
2. global.h不应该定义的函数，b- headers不应该初始化变量。
3. 编译时您应该使用-Wall -Werror，这将迫使您修复代码中所有不可靠的部分。
4. 要干净地获取exit()，您将需要#include <cstdlib> ( C++ )或#include <stdlib.h> (C)

< code >H115使用g++链接C++代码，以便包含C++库。用g++.完成整个C++编译可能是最简单的